X-Men director Bryan Singer had to bend the budget on the movie's sequel after he discovered his stars couldn't play chess.

British thespians Patrick Stewart and SIR Ian McKellen's characters, PROFESSOR X and MAGNETO, play chess in one pivotal scene of X-MEN 2 - and what should have been a simple scene became one of the film's most problematic.

Stewart recalls, "Bryan set it up and said, 'You're going to play chess. Just make some moves.' I whispered to him, 'I don't know how to play.'

"Sir Ian said he didn't know how to play either and I saw Bryan roll his eyes like, 'I can't believe I employed two actors, neither of whom can play chess.'"

"Then he said, 'Get someone on the set because we just need to believe they are making the right moves. Only in Hollywood could this happen.

"We arrive on the set and there's a guy there to instruct us in chess moves, a Canadian grand master! It was embarrassing. He was so over-qualified for the job.

"He was very happy however, because he'd never been on a movie set. After our tutorial, he wouldn't leave. He stayed all day and watched everything. I think he stood there mentally moving us all like chess pieces."