From the 1950s onwards, Jacques Cousteau was the man who taught the world about the ocean. He made more than 100 films of exploration for TV, won three Oscars and his documentary The Silent World took the Palme d'Or at Cannes. But the actor who plays Cousteau in new biopic The Odyssey says he was a complex figure, not always easy to like.
In Britain in the 1970s, Jacques Cousteau documentaries were a Sunday night fixture on BBC Television. He also became the most familiar French citizen for a generation of American viewers.
The French actor Lambert Wilson, now playing the diver and explorer on the big screen, grew up watching Cousteau on TV.
"For me he was a television hero and for most people of my generation he was a presence growing up," he says.
"I would watch with my grandparents and Jacques-Yves Cousteau - which is what we always called him - would always be near the top of any poll of people the French admired.
"There he was on this fascinating boat, The Calypso, with a group of happy, tanned colleagues always eating and drinking. And then they'd jump in the ocean and swim with the dolphins or a whale.
"It seemed a fantastic life - though as we show in the film he was very canny about showing the public what he knew they wanted. With a camera around he was like an actor.
"So 20 years after his death I was delighted to be approached to play him and I didn't hesitate. Well possibly for one moment, because I knew nothing whatsoever about diving. And I had to lose weight because Cousteau was very thin."
Father and son
One of the pleasures of Jerome Salle's film is the gorgeous underwater camerawork, much of it shot off Croatia. France's Mediterranean coast is mainly too built up now to pass for earlier decades.
Wilson loved exploring the clear waters but says the best location was one audiences may not expect - the Antarctic.
"Later in his life, Cousteau became far more interested in environmentalism, which is what took him there. And in a sense, how that change of heart came about is also the heart of the film," he says.
A lot of the drama comes from Cousteau's relationship with his son Philippe, who died in a plane crash off Portugal in 1979. Philippe is played by Pierre Niney and the two actors portray a father and son who can never acknowledge how much they need one another.
"In many ways it is Pierre who is the hero of the film and I'm the bad guy. Or, let's say, I am the hard, egotistical father who is always in America looking for money in television offices," says Wilson.
"I'm also a womaniser and his first wife (played by Audrey Tautou) isn't very happy.
"The family dynamics are complex - as Cousteau was himself - and there are points where probably the audience doesn't like him much.
"The two sons didn't go to school until they were eight and they were brought up in a very particular way. He gave them a huge understanding for nature but I think sometimes he forgot about them. It's something I can sympathise with."
'Untold love stories'
Wilson's father, who died in 2010, was Georges Wilson - famous in France as an actor and a director.
"I became an actor because I saw my dad doing all these extraordinary things on film or on stage and I wanted his approval. And the real subject of The Odyssey is the father-son relationship: Philippe also wants his father's approval but never really gets it.
"I think in general father-son relationships are untold love stories: it was exactly the same thing with me and my father."
In the film it is Philippe who persuades his father to take more interest in ecology.
"It may sound odd because of all his nature programmes - but originally he wasn't really a campaigner in the modern sense," says Wilson.
"So we see reconciliation between father and son and that's a high point - followed by Philippe's tragic death. Cousteau went on working without Philippe but I think the loss destroyed him inside: someone who worked with them told me that after Philippe's death, Cousteau was living life but with the music missing. I think he was empty inside."
So did Wilson ultimately feel sympathy for Cousteau or did he cut a cold figure?
"I return to my own father, who was almost the same generation. Men born in 1910 or 1920 were shaped by the war and the occupation in France. They could be hard people. When I told my father I wanted to be an actor and was coming to London to study, he told me I would be a total failure: I hadn't suffered enough in life.
"I think for them, growing up had been so hard that they didn't want to share their territory with anyone. They were like old lions.
"There is something harsh about Cousteau which certainly we don't ignore in the film, but we show something more admirable too.'
The Odyssey opens in the UK on 18 August.