Redford steals Cannes show with comeback film

Now a hardy 76, the leading man of "Butch Cassidy and the Sundance Kid", "The Sting" and "Out of Africa" carries "All Is Lost" by J.C. Chandor single-handedly, with just a few scripted lines.

He plays a retired man on an Indian Ocean voyage whose vintage sailboat collides with a shipping container and begins taking on water through a gash in its side.

Chandor dispenses with explaining the skipper's background -- he's not even given a name -- but presents Redford with all manner of trials to show off his acting chops and enduring physical prowess.

The director bagged an Oscar nomination for the screenplay of his 2011 feature debut "Margin Call" about a disastrous investment bank failure which premiered at Redford's Sundance independent film festival.

Breaking away from that picture's ensemble cast and complex plot, "All is Lost" is "an existential action movie", Chandor says. The movie premiered out-of-competition at the festival, which ends on Sunday.

Double Oscar-winner Redford, who has focused on behind-the-camera work and philanthropy in recent years, said that despite all the young filmmakers he had taken under his wing, Chandor was the first Sundance alumnus to hire him.

"This allowed me to just be an actor again, because that's how I started," he told reporters after a warmly applauded press preview.

"There's a lot of pressure and there's a lot of weight to being a director and particularly to being a director-producer so I loved it and I would like to continue that. I don't want to have to act and direct every time I go out."

Chandor, in his late 30s, said he had chosen to cast Redford as an "iconic symbol" for his own father's generation.

"You're taking this person that essentially so many people have a relationship with," he said, referring to Redford's long screen career.

"I think that allows the audience to almost use him... as a stand-in for themselves."

Faced with violent storms, circling sharks and dwindling supplies, Redford's character relies on his own ingenuity to survive.

The hobby mariner has only primitive navigational equipment and nautical maps to guide him as he tries to chart his way to a shipping lane he hopes will lead to his discovery and rescue.

Several scenes were shot in Mexico, at the world's biggest film tank specially built for the blockbuster "Titanic".

During one terrifying squall, his boat, the Virginia Jean, repeatedly capsizes and rights itself, as the sailor is hurled around the cabin.

Redford said he did as many of the stunts as he could himself.

"It was very tough. (Chandor) was relentless in his vision, which I appreciate, but he was also... very respectful of me and my wellbeing," he said.

"So I think because of that I was encouraged to want to give him more and more and more. So I thought if I did some of these things myself it would be good for him but also pretty good for my ego," he joked.

Redford said the biggest challenge was to develop a character using only a few words of dialogue, as the film dispenses with the kind of foils such as a volleyball and a talking tiger used in sea adventure movies like "Cast Away" and "The Life of Pi".

"I've always valued silence and quiet and when you take that into a dramatic form it becomes really interesting," he said. "It forces you as an actor to be completely inhabiting your role. If you're not, it's going to show."

Asked about his staying power, Redford said his choice to live away from Los Angeles, in the mountains of Utah, had let him avoid succumbing to the "temptations that might not further your artistic desires".