CANNES -- Even at 77, actor-director Clint Eastwood refuses to retire. But he is winding down his acting career, he told the Cannes Film Festival yesterday.

"I am gradually, as you may have noticed, working my way around to spending more time behind the camera than in front. It is an inevitability," he told a press conference.

Eastwood, a native of San Francisco, turns 78 on May 31. He is a little sensitive, if bemused, about his age. When a flamboyant Russian journalist offered a birthday salute, Eastwood muttered, grinning: "It's at least a week away, so let me be in peace!"

Eastwood did not take a role in The Exchange (or Changeling or whatever title his new directorial effort eventually gets released under because that has still not been settled, contrary to earlier reports). It played in Cannes competition last night with Angelina Jolie and John Malkovich co-starring.

Dignified, methodical yet white-heat angry, the drama is a searing indictment of widespread corruption in the Los Angeles Police Department in 1928, in a true story about the gross mistreatment of a single mother when her young son goes missing.

"The reason I'm not in it is that I'm too young to play one of the boys," Eastwood joked about the many roles for children in the film.

"There was just no role in it for me."

Eastwood debuted in film with an uncredited appearance in Revenge of the Creature (1955), in which he had one pathetic line of dialogue: "I've lost my white mouse."

As a director, Eastwood is now a titan of American cinema, having won an Oscar for his work behind the camera. As actor-director, his next effort is Gran Torino, in which he will star as a Korean War vet who goes into action when his vintage Gran Torino car is stolen.

Aching tale

Angelina Jolie felt intimately connected to her true-life heroine in The Exchange, even though Christine Collins fought LAPD and City Hall corruption in the 1920s to champion her son.

"This is personal but it's true. I lost my mother a few months before the film and, to me, (Christine Collins) is very much like my mother. My mother was very passive in many ways, and very, very sweet. But, when it came to her children, she was a lion.

"Christine reminded me of my mom and it was a way for me to revisit my mother after her passing and spend time with her. So that was very nice."

Jolie's late mother is Marcheline Bertrand, an American-born actress of French-Canadian and First Nations heritage. She died on Jan 27, 2007, of ovarian cancer at the age of 56.

Truth trumps politics

Eastwood had no problem attacking the sordid history of the LAPD in The Exchange, even though he is known to be a moderate Republican and has spoken in favour of controling crime. In response to a Sun Media question yesterday, Eastwood said that police and politicians in L.A. have descended into corruption repeatedly and should be brought to justice each time.

"It seems like every two or three decades in Los Angeles, the police department or the political structure has gone through some sort of revolution within where they have been caught in some sort of corrupt activities. And 1928 is one of those periods."

Eastwood said yesterday that truth triumphs, in life and on film.

"Truth is the most important thing and most stories of intrigue are trying to get at the truth, and telling the truth is one of the most important things for an actor. Being truthful is just the greatest virtue on the planet. That is what makes any drama interesting, I think."

Cannes awards

Eastwood is not necessarily gunning for gold at Cannes.

But he does not mind competing.

"It seems like, if you are going to come to a film festival that has a competition, you might as well be in the competition," Eastwood said.

"Whether you win something or not is not the point of it. You just come here to be a part of it. To play it out of competition is kind of playing it safe and saying: 'We're above that!' I'm not above that. It's nice to be here. Whatever happens, happens."