Sir Michael Caine is a "terrible giggler" who makes filming difficult.
The veteran actor caused problems on the set of 'Harry Brown' because he and co-star Emily Mortimer kept making each other laugh, delaying filming as takes had to be redone several times.
Emily explained: "He's got a twinkle in his eye and he's a terrible giggler which is fatal for me. The minute that I can tell that someone has the propensity to crack up it's impossible for me not to. So we had a bit of a difficult time.
"I have this thing in the movie where I get whiplash and I was told by some stunt guy that it was very important that I held my neck at all times. I kept thinking about it and had my hand glued to my neck the entire time and Michael just couldn't stop ripping me about it.
"We got in this running joke about this thing and then of course whenever it came to the point where I actually had to do a scene with him with my hand on my neck and I can just see this little glimmer in his eye. We both just cracked up and ended up having to do it over and over again. We couldn't get through it."
Despite his tendency to giggle, Emily insists Michael was the most professional person she had ever worked with.
She added: "He's just the most expert professional dude I've ever really worked with, I think, but he's been in it for such a long time and so he knows what he's doing. He comes, turns up and is completely prepared. He delivers an amazing performance and there's no nonsense, no complaining or high maintenance silliness going on. He's just incredibly professional and easy going and cool. I loved him."