He subsequently emigrated with his family to Canada, where he and his wife focused on raising their daughters, Zaneta and Amanda. They returned to Hong Kong after four years as the girls entered university.

In 2000 Cheng ventured into producing when director/producer Peter Chan Ho-sun invited him to produce a series of horror movies by brothers Danny and Oxide Pang. That led to a series of collaborations on movies by director Barbara Wong Chun-chun.

"The producer's job suits me as I can go to bed at 10pm. While working as the chief operating officer of Commercial Radio [1998-2004], I developed the habit of going to bed early and rising early."

But that lifestyle wasn't feasible if he took up directing because filmmakers often have to work through the night, several days in row, to stay on schedule, he says.

Moreover, "as a producer, I initiate the script. Everybody respects me and listens to me. Up until post-production, a producer is involved in the whole process."

Then Media Asia boss Peter Lam Kin-ngok proposed a film project about a couple working through a long, on-again off-again relationship that changed his mind.

Cheng loved the tale, not least because it recalled a similar film that he tried to get off the ground a decade ago while he was still at Commercial Radio.

"The love story, set in a coffee shop, is about a couple for whom frequent threats of break-up have become the glue that keeps them together."

Inspired by an assistant's dream of opening a cafe selling macabre memorabilia, he came up with the idea for a movie set in a coffee shop that memorialises the death of love. "I pitched it to movie investors then, but no one was interested," he says.

Now it has become the main storyline in : actors Ekin Cheng Yi-kin and Chrissie Chau Sau-na play a couple whose floundering coffee shop revives after he hits upon the idea of installing a cabinet where customers can display mementos and share thoughts about their failed relationships.

The movie reflects how relationships often play out today, Lawrence Cheng says.

"In the past, couples didn't threaten break to things off all the time. Nowadays, people say 'let's break up' more than 'I love you'. They break up in the morning and reconcile in the afternoon.

"As a director, I don't want to judge whether it's good or bad; I just want to show how people view love today."

Cheng's team converted the space once occupied by a pet shop in Sheung Wan into the charming backyard cafe that he envisaged for the movie.

"We spent more than HK$1 million constructing the set. I wanted to see dappled sunlight coming through the trees and patrons savouring coffee and desserts nearby."

It's no accident the Sheung Wan that Cheng portrays evokes a hint of old Europe, with its stone staircases snaking uphill and buskers performing in underpasses.

He wanted to capture the character of the old district before it all gave way to wreckers, he says, citing Pound Lane, the site of the earliest Chinese settlements, where an escalator project will likely bring the loss of heritage features.

"Hong Kong has a lot of beautiful places but the government keeps destroying them," Cheng says.

He has also worked some transformative magic on sultry actress Chrissie Chau, casting her against type as a down-to-earth young woman struggling to get her forty-something boyfriend to grow up.

"People doubted my choice. They queried whether she could play a character with lots of inner turmoil. But I was bold and believed in my intuition. Three days into shooting, she was already in character.

"She's a pliant actress. Besides her sexy pout and low necklines, she shows that she can indeed act," Cheng says.

Cheng is proud of his ability to spot hidden talent in actresses. He reckons the key to acting lies in tapping personal experiences to help conjure up emotion. That's how he got into character for his role in as the husband of a woman played by Carman Lee Yeuk-tung.

On and off set, he treated Lee with the same care and consideration as he did his own wife. It certainly helped her play the grieving widow when his character died, he adds.

Since last year, he has also taken on a new job training TVB's newly recruited artistes, which allows him to share more acting tips. The acting exercises can be intense: a one-minute performance by each trainee is followed by 15 minutes of detailed critique from Cheng. It has been exhausting, he says.

"But they call me dad, as I teach them more about life lessons than actual acting skills. I teach my two daughters in the same way. You have to take criticism in your stride, and be grateful for it. In life, especially in show business, your feet have to be firmly on the ground, as hubris won't get you anywhere."

Cheng learned the hard way when he first went into radio broadcasting. He freelanced as a DJ while studying journalism at the then Baptist College, and RTHK invited him to host a pop programme after graduation. But his performance was so dismal they soon relegated him to a 2am slot.

"I thought playing music would be easy, but it wasn't. They took me off the programme after only two months," Cheng says.

He spent nine months on the late-late show, learning the ropes of presenting an entertaining radio programme.

"I'm good at writing. So while other DJs improvised, I prepared a script for the programme. I wanted to turn my strength in writing to my advantage in radio."

That strategy was vindicated; , a radio drama series he created in 1986, proved to be a hit with spin-offs in books, stage, television and film (in which he took the lead role).

Cheng also became a popular television emcee, presiding over charity concerts, variety shows and beauty pageants. He even hosted TVB's pop music show, for a decade.

All the same, he was flabbergasted when the station asked him to host the show again last year.

"I have stopped listening to new songs for many years. I can't even tell who's who in the line-up of new singers and bands. In the past, one singer could bring the house down. Now, there are many other entertainment options. It's very difficult to please audiences who think the new singers are no match for past greats like Jacky Cheung Hok-yau," he says.

"When I see the new singers on , I sympathise. They sing quite well and put their heart into it, but lack confidence. But [Canto-pop's] golden period has passed and we have to go with the times."

Keeping up the times, Cheng set up an online radio station, ChannelEgg, two years ago:

"I want to make use of technology to do something. Of all the media, I love radio broadcasting the most."

The station doesn't carry much content because he has been too busy to produce material, Cheng says. But he has always wanted to return to broadcasting, whether online or at a regular radio station.

"I will do the radio programmes I love once my daughters get married and I can stop worrying about them," he says.

Now that his eldest daughter has completed her master's in English literature in the US and his younger child is about to begin a master's in archaeology in Britain, Cheng, 59, says he has the financial resources at his disposal to finally take on projects that interest him.

"People at my age only do things they want to do. That's why I can go back to directing, which requires all my energy and attention. Although I can complete shooting in six weeks, what takes a real toll is the promotion work. I've been to five cities on the mainland doing marathon interviews from morning to night."

For his next movie, Cheng hopes to tackle relationships between empty nesters such has he and his wife.

"My wife and I had children 10 years after we married. For 18 years after they were born, we devoted ourselves to our daughters and paid less attention to each other. When they left to study overseas, it was like we didn't know each other as we had forgotten our likes and dislikes. So we had to get to know and love each other again," he says

"Now, every Sunday, I play soccer in the morning and then pick up my wife from her church service. Afterwards, we go for brunch and watch a movie in the afternoon. I want to make a movie about a man who grows old and falls in love with his wife again after their children have left home," he says.