Ashlan Gorse and her husband, Philippe Cousteau, are both human. It's worth making this point immediately because when you encounter the elongated, slender glow of them - that beaming wattage of people used to being loved by the camera - it's like shaking hands with a couple of charming aliens. Having landed in the desert that is the 11th-floor Starwood Preferred Guest Lounge of the Sheraton Hotel in Tsim Sha Tsui on a Friday afternoon, they look beautiful but faintly unearthly. Are they for real?

They come, of course, from Planet Hollywood, where they live, and its close cousin, Galaxy Television, where they work. If you recognise them - they're not yet stratospherically famous, although they're getting there - it's probably because you've seen Cousteau on CNN, describing his global adventures around the world's oceans, and Gorse on E!, interviewing celebrities on the red carpet.

You may also recognise Cousteau from a Gap campaign currently running here. Central MTR station has several enormous images of him (looking like a cross between Ryan Gosling and Jake Gyllenhaal), lassoed within a stripey scarf being worn by his equally glamorous sister, Alexandra. In 2010, the siblings were on Vanity Fair magazine's Next Establishment list for their environmental work, having, a decade earlier, launched EarthEcho International, an environmental-educational non-profit organisation, with their mother, Jan Cousteau.

And, yes, they're related to that Cousteau, the great Jacques, the Frenchman who co-invented the Aqua-Lung and who, from the 1940s onwards, introduced an ignorant world to a parallel universe that did, indeed, teem with truly gorgeous aliens: not a speculative one in the sky but a real one beneath the surface of the seas. Jacques had two sons by his first wife; Jan married the younger. She was three months pregnant with her second child when her husband was killed in an accident on his boat. The baby, born in January 1980 in California, was named after the father he would never know: Philippe.

Part of the glow from Les Cousteaux is surely attributable to newlywed bliss. The pair were married in France, in homage to Philippe Cousteau's ancestry, at the end of September (a chair was left empty, next to his mother, in honour of his dead father.) The day before this interview, as Gorse points out, was November 28, which happened to be both Thanksgiving and their two-month anniversary. They spent it in Hong Kong because Cousteau, in his role as president of EarthEcho International, was one of the speakers at a gala dinner that night titled "The World in 2014" and organised by The Economist.

Gorse, who left E! in June but is still fond of the words "cool" and "awesome", is now adapting to her new role as a member of the EarthEcho International team. This involves, among many other things, learning to travel light to exotic places; Cousteau only takes a carry-on.

"It was hard, but I did it," she admits of packing for this trip.

Unfortunately, the Cold Weather Warning caught her by surprise; a trip to Shanghai Tang to buy a jacket is planned for after the interview.

The pair spent the morning getting to grips with Hong Kong's specific issues.

"We met the folks from the AFCD," says Cousteau, consulting his phone-diary. "That's the Agriculture and … " There's a short pause into which Gorse helpfully offers "Defence?" before Cousteau continues "… Fisheries and Conservation Department".

Shark's fin was on the conversational menu. A senior endangered-species protection officer spoke to them about his work.

They then visited Sing Yin Secondary School, near Choi Hung.

"It's a Catholic school, all boys, really cool," says Gorse, enthusiastically. "It's just won the greenest school award in the world."

"Let's see," says Cousteau, carefully googling, before reading out: "The Centre for Green Schools at the United States Green Building Council has deemed two schools winners of its Greenest School on Earth Award for 2013 - the Uaso Nyiro primary school in Laikipa, Kenya, and Sing Yin Secondary School in Hong Kong. OK, so it's Kenya and Hong Kong."

According to the citation, Sing Yin faces environmental problems, including dangerous air-pollution levels and a severe waste-management problem. But it has two green roofs, an organic farm, low-carbon cooking programmes and an aquarium - hence the award.

"I showed them video clips of me in the Arctic," says Cousteau. "Kids are inspired by that. And we showed them videos from the great white shark dive we did together, and talked about shark's fin, pollution and food problems."

"We know shark's fin is a huge problem," agrees Gorse, earnestly. "In California now, you can't buy it or sell it. Coming over here, it's almost a foreign concept - it's on the menu! Honestly, it boggles the mind. But one of the hardest things to fight is tradition and it's up to the young people. We always snicker a little bit because it's cartilage, it's like eating an ear."

Cousteau says, "What's ironic is that people eat shark's fin to gain vigour. But sharks are high in mercury and it tends to concentrate in the fins. And mercury causes hair loss and depression and impotence. People eat these fins and they're kidding themselves, it's going to have the opposite effect."

People who watch some of the early Jacques Cousteau films nowadays are often flabbergasted at the blithe way he killed, then chopped up, sharks on his famous boat, Calypso.

"People forget it was a journey for all of us," says his grandson. "When he started in the 1940s, it was a brand new world. The shift happened in the 1960s, when he went back to places he hadn't seen for a decade and saw the change in those systems. That's when he said it's not about exploration - it's about conservation."

One of the Sing Yin schoolboys came up with what they both agreed was a terrific question.

"He asked, 'Can people who are a part of the problem also be a part of the solution?'" says Cousteau.

The idea behind EarthEcho is to encourage children anywhere in the world to take action and influence their surroundings. The focus is on science lessons via an educational programme called EarthEcho Expedition: Into the Dead Zone. (You can watch some of the accompanying video footage at; the film shows children in the Chesapeake Bay watershed, on the eastern coast of the United States, being taught to recognise conservation problems and nag everyone around them to think of solutions.)

To that end, the pair were planning to have a look at Ocean Park's educational outreach programmes, and they thought they might go over to Macau, to check out opportunities there. Cousteau is co-founder of Azure Worldwide, which offers environmental expertise to clients including a skin-care company and eco-tourism ventures in Costa Rica. It has also developed, with the University of Virginia, an interactive game that simulates the Chesapeake Bay watershed, with its 100,000 rivers and streams.

"Non-profits can only go so far," he says. "We need to recognise what businesses can do, how they can create money doing the right thing."

How does Gorse fit into this picture?

"I was always into animals and animal protection, ever since I was growing up," she begins. (On cue, Cousteau pulls up a photo of Aurora, the Siberian husky she'd adopted just before they met.) "Thank God I have parents who'd support the crazy things I did. If my dad found a snake, I'd take it to the woods. I was always taking these homeless birds and homeless cats home."

As it turns out, one of the most interesting things about Ashlan Gorse isn't her name (which, she says, her parents made up, so she's amazed how many other Ashlans she's since found on Facebook and Twitter) or her E! News reports on, say, zumba or Johnny Depp or Taylor Swift. It's that when she was almost eight, in 1988, her home in Raleigh, North Carolina, was destroyed by a tornado as she, her older sister and her parents hid under the stairs.

She never talks about it in public, she says thoughtfully - Valley Girl mannerisms put on hold - because no one's ever asked.

"It was such a fluke. My father heard it, he knew what it was. That was on Thanksgiving night." (In fact, it was a few days later - on November 28.) "He went to get my sister out of bed, my mom went to get me."

Cousteau: "Your roof came off, didn't it?"

Gorse: "The roof came off, the house was totalled. It was 2am … My parents were so upset, they didn't rebuild there, we moved away. This is going to sound so horrible but it was such a traumatic experience I kept it locked up. I didn't remember it until I saw that [1996] movie, Twister. And I had a panic attack, right in the middle of the theatre."

Cousteau (watching her): "Is that the one we saw a few years ago? There was a film we saw, it had a tornado, and you started to hyperventilate."

Gorse (quietly): "No, that was a different film."

To what extent, does she think, have those events influenced the exuberant, daredevil character she likes to portray on television?

"It's funny that this doesn't usually come up in interviews because it shaped a lot."

Later, she says, with some feeling, "The recent typhoon [Haiyan] is so horrible. Typhoon damage happens when they hit land, and as humans we've decided to destroy mangroves and hurt coral reefs. If we don't have barriers, the devastation is worse and that is scary."

At around the equivalent time in his childhood, Philippe was beginning to realise that he didn't have a made-up name. His was the same as his unknown dead father's and it had international weight.

"People assume I grew up rich, on Calypso, having adventures. But I grew up with a single mom who worked. I saw my grandfather a few times a year. At different stages, it felt traumatic not having a father. And then there was the whole episode with Steve Irwin."

Irwin was the Australian wildlife expert who died in 2006 when a stingray pierced him with a barb in the chest while he and Cousteau were filming an underwater documentary for Animal Planet called Ocean's Deadliest.

"Having someone die that you're trying to save with CPR, and he dies in your arms, and the circumstances are eerily similar …" Philippe begins.

He sounds uncharacteristically uncertain and Gorse puts her hand on his knee.

"He died on an expedition, my father died on an expedition. He was 44, my father was 38. The ages of his daughter and son were like my sister and me.

"Taoism helped me a lot. Instead of locking myself up in a room, I want to live a full life. One of the things we're going to do in Hong Kong is visit a Taoist temple." He smiles. " The Tao of Pooh is a book I keep on my bedside table."

Gorse says, "Well, technically, it's on my bedside table because I'm reading it at the moment."

When they met, in July 2010, Cousteau had just spent six weeks in the Gulf of Mexico reporting on the BP oil-rig explosion for CNN. He was giving a speech in Los Angeles and Gorse happened to be present. Afterwards, they talked in the bar until, he says, "they were vacuuming around us". Cousteau was impressed by the fact that Gorse, on a movie junket in Bora Bora, had leapt into the sea in her bikini to swim with sharks. "I thought, 'That's my kind of girl'."

A psychologist might say they recognised something in each other beyond the attractive externals.

Cousteau says, "I agree, it wasn't just …" and Gorse finishes the sentence, "physicality. I am a huge water baby. I was swimming when I was a baby. I always wanted to be a mermaid. When we have a child, it's my chance to have a merbaby."

Of course, there are, as Cousteau frequently points out in his talks, seven billion people in the world already …

"It's true," says Cousteau, evenly. "But I think the challenges we face should not cause us to give up on life. I think our choice will be to have children - although not too many."

"Definitely not too many," agrees Gorse.

Jacques' relationships with his various offspring have, it must be said, muddied the family waters. He took his first son, Jean-Michel, to court for opening a resort called Cousteau in Fiji; Jean-Michel was subsequently legally required to use his full name to distinguish himself from his father. Jacques had two other children in secret by a woman called Francine Triplet while he was still married to his first wife, Simone. One of these children, Diane, was born in 1980, the same year as Philippe, his grandson.

After Simone died, Jacques married Francine. She now heads the Cousteau Society. Her son by Jacques, Pierre-Yves, has formed a non-profit named Cousteau Divers, to unite divers in protecting marine life. Meanwhile, Jean-Michel has set up the Ocean Futures Society and his son, Fabien, is founder of Plant a Fish. The world's depleted seas would appear, at least, to be well stocked with Cousteaus.

Philippe Cousteau will only say good things about the family name he carries and has now bestowed upon Gorse.

"When I was younger, it was more difficult," he says. "But as I got older I came to terms with the name of Cousteau. The influence of Taoism meant letting go of all the anger and frustration and negativity. The legacy is being proud of it and seeing it as an opportunity to have adventures."