From dropout to fat cat, thanks to A Street Cat Named Bob

James Bowen was a down-and-out drug addict before he was saved by a street cat that turned him into a bestselling author.

Bob the cat came into Bowen's life nine years ago when he was sleeping on the streets of London and addicted to heroin. "I'd just moved into supported housing and signed up for methadone treatment when I saw this injured cat outside my building. I took care of its wounds and tried to send it on its way, but it wouldn't leave. Being responsible for something was how I managed to get clean," Bowen says.

The cat knew what it was doing. It learned a couple of tricks from Bowen and happily sat in his guitar case as he busked around London. The duo became a local sensation and, in 2010, literary agent Mary Pachnos came calling. Pachnos, who had a hand in turning Marley and Me by journalist John Grogan into a global bestseller, had noticed the two performing near her home and started talking to Bowen. Realising she had found another great animal tale, she gave Bowen an advance and recruited a ghost writer to help put together A Street Cat Named Bob, which in 2013 shot up The New York Times' bestseller list before being translated into 40 languages, including Chinese.

The story has a lot of mileage. A Hollywood movie is in the works, the eighth book - a children's tale of how Bob rescues a stray puppy - comes out in September and Bowen is opening a Bob-themed café for charity. By his estimate, he has made nearly £1 million (HK$12.1 million) from advances and royalties.

Bowen, who was recently in Hong Kong without Bob for some R&R before returning to Britain for a punishing book tour, still can't get over how lucky he's been. "You know I'm a publishing world whirlwind, right?" he says in his Four Seasons suite. "The next four months will be crazy. Bob and I will be shoved everywhere."

Bowen's sober black suit cannot hide his boyish delight over his great change of fortune. Well-rehearsed lines about the joy of changing people's lives are delivered, but a lunchtime tipple has relaxed him sufficiently for him to whisper conspiratorially about "how crazy" it all is. "Do everything in style - that's my motto," he says, as he puts on his sunglasses and sashays towards our photographer.

This is the life Bowen dreamed of when he left home at the age of 18, intent on becoming a rock star, before it all went down the drain. Now, he flies first class to Hong Kong for his holidays, glamorous personal assistant in tow, and calls the Four Seasons his favourite hotel. He's paid for the trip himself, although the hotel upgraded him to the HK$19,000-a-night deluxe suite.

Bob is trying to sleep back in Tottenham, but Bowen is eager to show him off. He dashes over to his iPad several times during the interview to shout instructions at the cat's carer over a Facetime video connection: "Ron, get Bob to do a high five on camera," or "Ron, get Bob to sit up."

Bob accedes to every demand with extraordinarily good grace, provided there's a treat at the end. Ron, however, is beginning to sound fed up after the fifth high five and, here in the hotel room, the assistant has to put her Louboutined foot down and issue a stern, "I think that's quite enough".

Bowen explains why he loves Hong Kong and why he's come back eight times. "It is always changing, unlike the UK," he says. Hong Kong reminds him of futuristic cities in the comic books he likes. "When the hover board from Judge Dredd is invented, it will be here first," he says. He tends to stick to tourist paths that lead to Lan Kwai Fong bars and Michelin-starred restaurants. "We've eaten half a cow here since we arrived. Tonight, we are going to try the Chinese restaurant downstairs," he says.

Bowen's mother has told the British tabloids she's worried about his spending habits. Gleefully undeterred, Bowen is convinced that he will continue to sell books and raise a lot of money for charities. As for Bob, Bowen says he is in good health and should live for at least another 10 or 15 years.