The Love Actually star got his start in the theatre, and even once toured in a company with fellow British stars Julie Walters and Pete Postlethwaite.
But despite successful stints on Broadway and in London's West End, the actor still has panic attacks before stepping into the spotlight.
He says, "It gets worse and worse. It's like an illness. You get a shortness of breath, light-headedness and you feel nauseous.
"When I do a play, it's like agreeing to be ill for a couple of months. It's absolutely normal and appropriate to be scared. Everyone is scared - I know really, really famous people who are terrified every time they walk on to a stage."