He is, perhaps, the world's most unlikely superstar. Despite a lifetime of fighting disease and defying medical predictions, Professor Stephen Hawking has become the planet's most celebrated cosmologist.
Divorced twice, with three children and a jet-set lifestyle transcending the confines of academia, he turns 70 next week.
A rare insight into the man will be given this week by his children and some of his closest friends when they pay tribute to him on Radio 4.
Diagnosed with motor neurone disease at 21, he was warned he might not live to see his 22nd birthday. Yet he has spent decades working on groundbreaking theories and the nature of the universe.
Hawking has turned his disability into a trademark and has become a cultural icon, with appearances on many TV series. His appeal extends to lads' mags: Nuts voted him British Bloke of the Year in 2011 – beating Daniel Craig and David Beckham.
In 1988, he published A Brief History of Time, which sold 9 million copies, the first of a series of blockbuster publications.
There are contenders for his title as the world's top pop scientist, led by Brian Cox. But none has a personal profile to rival his, let alone a comparable scientific track record. His ability to generate controversy – statements such as "Science makes God unnecessary" and his dismissal of the afterlife as a "fairy story for people afraid of the dark" – has fuelled his fame.
His son Tim says his father developed strategies to escape relentless public attention: "He had a pre-set phrase on his voice machine. He used to pretend that he was a doppelganger for Stephen Hawking and not the real one, which didn't fool anyone."
The pressure of celebrity played a part in the breakdown of Professor Hawking's first marriage. And he hit the headlines again when his second marriage, to his former nurse, ended in 2006 amid rumours that she had abused him. Police investigated reports of abuse on at least two occasions, in 2000 and 2003, but no charges were ever brought.
Domestic affairs aside, there is little doubt he has enthusiastically enjoyed the trappings of fame. One of his more unlikely chums is Peter Stringfellow, the nightclub owner. He recalls when Hawking came to his club. "I said to him 'I have my own views on the Big Bang and string theory – would you like to talk about them or just see the girls?' And in just two words it came out: 'the girls'."
Professor Hawking has received a stream of accolades and awards for his scientific work. To Ben Bowie, executive producer of the television series Into the Universe and Grand Design, he is a "rock star of physics". Giving an insight into the academic's sense of humour, he said: "We'd just transmitted one of the shows and he said 'Ben, look at the sun'. So I looked out of the window and his nurse said, 'He doesn't mean that' – and she reached in her handbag and pulled out The Sun and on page 3 was Cindy – "a great fan of Stephen Hawking".
In truth, the scientist, who spent 30 years as the Lucasian Professor of Mathematics at the University of Cambridge, is no nerd. He is equally happy taking to the dancefloor in his wheelchair at a university ball or partying with scantily dressed hostesses at Stringfellows. He defies attempts to pigeonhole him.
And his daughter Lucy says her father loves the limelight: "He is a bit of a impresario at heart, and he loves a big show, a big stage, bright lights, whether it's him on stage or whether it's watching the spectacle."
The professor is philosophical about the hand fate has dealt him: "I'm sure my disability has a bearing on why I'm well known. People are fascinated by the contrast between my very limited physical powers and the vast nature of the universe I deal with," he says on his website.
Reflecting on his forthcoming 70th birthday, he remarks how he was born "exactly 300 years after the death of Galileo. However, I estimate that about 200,000 other babies were also born that day."
Lord Professor Martin Rees, the Astronomer Royal, paid tribute to his friend: "Even his mere survival seems a medical marvel – fully deserving of celebration and razzmatazz. But he hasn't merely survived; he has become arguably the most famous scientist in the world."
A global star: From cartoons to chat shows
From cartoons to sci-fi series, pop music to chat shows, Professor Stephen Hawking is an instantly recognisable global brand. He makes regular guest appearances on The Simpsons – Lucy, his daughter, used to work with one of the writers. His Simpsons character is so popular that it has been made into an action figure.
The best-selling author and TV presenter is also a sought-after speaker who can fill the Albert Hall for lectures. Bands such as Pink Floyd have sampled his distinctive voice, and The Manic Street Preachers 2009 album Journal for Plague Lovers features the track "Me and Stephen Hawking".
The scientist was played by Benedict Cumberbatch in the Bafta-nominated Hawking in 2004, set during his postgraduate days at Cambridge. Professor Hawking has also popped up on chat shows in the US – once taking part in a sketch with Jim Carrey.
The young pretenders: Boffins with a screen presence
Professor Brian Cox
Physicist, TV presenter and former D:Ream keyboard player. Not in the same universe when it comes to academic credentials – degrees from Manchester Uni followed a D in his maths A-level.
Dr Yan Wong
After Cambridge, he took a PhD in computational and mathematical modelling of self-incompatibility systems in plants. Co-presents BBC 1's 'Bang Goes the Theory'.
Dr Basil Singer
Physicist with a PhD in quantum chaos. He is an extreme sports enthusiast who runs a robotics company. Has presented science shows for many UK channels, as well as in the US.