Kenneth Branagh felt stupid when he realised he'd included Michael Caine's most famous Alfie line in his new film without noticing.
Caine utters "What's it all about?" during a tense scene in new thriller Sleuth, and it was only when audiences started giggling about the line that Branagh realised what he'd done.
He says, "We took this film to the Toronto Film Festival in Canada and there was a big laugh when suddenly Michael Caine's character is holding a gun and saying, 'What's it all about?'
"I was puzzled at first and then, 'Duh!' You would have thought Michael would be the one to spot that, but nobody did."
Ironically, Caine's co-star in the gun-toting scene is Jude Law, who played Alfie in the 2004 remake.