The two men star opposite each other in the comedy movie, in which Josh plays a Hollywood fixer in the '50s while George is in his element as a famous movie star. One scene required Josh to hit his co-star, and to make it feel genuine the actor focused on the many reasons why people may want to slap the former bachelor, who tied the knot with his wife Amal in September 2014.

"Everybody in the whole world wants to go for it," Josh grinned to "All the times he ever said he was going to be single forever, the perpetual single man, and all the women who felt like they were losing out, and all the men that hated him because he was so handsome and all their women wanted him... I slapped him for all those people.

"We had grand fun that day. I kept it a little more serious than he did that day. Usually I’m the instigator of a lot of clownish behaviour, but he stayed true to form that day and I tried to keep it... because he didn’t have to do anything, he just had to look like an idiot and be slapped."

Hail, Caesar! boasts an A-list cast, with Channing Tatum, Jonah Hill, Scarlett Johansson and Tilda Swinton just some of the other big names. It's helmed by the Coen brothers, who Josh has worked with before on films such as No Country for Old Men, and the actor thrived amongst his co-stars, especially one.

"Ralph Fiennes... are you kidding me?" Josh gushed. "I f**ked up that whole scene because the guy’s doing a scene to me and he’s so perfect on the first take, and there was this pause and I was sitting off-camera - I wasn’t even on film - and there was this pause and I’m like, 'God, even the guy can hold a pause for like, super long, you know? That’s totally unnatural but how is he doing it? He’s still compelling!'"