BERLIN: George Clooney whistled a tune and sang the praises of Belgian beer at the Berlin film festival for the international premiere on Saturday of his World War Two art caper "The Monuments Men", but reality had already given him publicity money can't buy.

The premiere of the film which has been released in the United States to mixed reviews was one of the most anticipated events of the festival, where four German films are among 20 seeking the top prize.

Earlier in the day, the festival saw the press premiere of director Dominik Graf's sumptuous historic film "Beloved Sisters" based on a love triangle involving the 18th-century German poet Friedrich Schiller.

But it was Clooney's presence that created a huge queue of press to attend his news conference, where he also acknowledged that reality had caught up with his film right here in Germany.

The discovery last year of a huge trove of artwork in a Munich apartment has created a flurry of news about paintings and other treasures stolen or expropriated by the Nazis and still awaiting restitution to their rightful owners.

"We've had a long three-year conversation with the guys here at Fox (the film's distributors) to get the news to hold the story," Clooney joked, before turning serious.

"It's a story that's going to keep coming up because there's still an awful lot of art still missing and will be found in lots of people's basements. It just happened to be one rather amazing find, one and a half billion dollars....It's an amazing conversation to have, the responsibility of getting back the art to people," he said.

Clooney, who enjoys clowning at festival events, was goaded by a questioner to whistle the theme to the movie, which she said was a quote of the cat theme from Prokofiev's "Peter and the Wolf". But in Clooney's rendition, joined by co-start Matt Damon, it only seemed to have the first three notes in common.

A questioner from Belgian media asked why the film, partly set there, was not filmed there. Clooney said this was for cost reasons but he said he had visited Belgium in preparation for the film and had enjoyed the beer.

Asked repeatedly why he'd chosen this story for one of his biggest budget movies, Clooney said the historical events had grabbed him, much like the war action stories of his youth. This one, he said, had an interesting twist.

"Hollywood does like a good World War Two story but this seemed like a story I didn't know. It wasn't a megapatriotic film but a chance to talk about a unique group of people who did something for the first time in the history of war, which is the victor didn't keep the spoils, they gave it back."