Practical joker George Clooney played a prank on his father by dedicating his latest film to his memory even though he is still alive.
The Hollywood star invited his father, a former TV journalist, to a special screening of Second World War film The Monuments Men.
Matt Damon, who co-stars in the film about a group of art experts searching for stolen paintings, told Graham Norton that Clooney was always "playing pranks".
He told the chat show host: "To give you an example, his dad is in the movie and George runs it just for him. As the credits rolled, it said, 'In loving memory of Nick Clooney'.
"His dad says, 'What the hell, George?', and George goes, 'Well dad, the movie doesn't come out for six months. It's much cheaper to take these things off the credits than put them on!'.
"So that's who you're dealing with and you have to understand that going into a movie. It is so funny to him."
Damon is on tomorrow's edition of The Graham Norton Show with co-stars Bill Murray and Hugh B onneville, who revealed he was not first choice for his role in the film.
The Downton Abbey star said: " I got a very dry letter through my agent saying, 'Dear Hugh, for your attention ... produced by ... followed by millions of names of the producers and starring Bill and Matt and everyone else, and then at the bottom another name for my part which they'd failed to wipe out."
Murray, whose career includes Ghostbusters and Groundhog Day, explained how he prepared for his part in Lost In Translation - set in Tokyo - by learning the language with a phrase book called Making Out In Japanese.
He said: "It was great. I would take the book with me to dinner at a sushi bar and say to the chef things like, 'Can we get into the back seat?', 'Do you have a curfew?'. And, 'Do you mind if we use protection?'. And these guys had big, big knives! I had a lot of fun with it."
:: T he Graham Norton Show is on BBC1 tomorrow at 10.35pm.