Clive Owen is saying that he almost turned down his role in Inside Man because of the requirements to act in a mask and shades through most of the film. Frankly I would have thought it would have made things easier for him, just that pesky American accent to deal with, and perhaps cover by the muffling of the mask!

From TeenHollywood.com through Digital Spy he says...

"I really had to think about it (accepting the part). An actor uses their face to express themselves, that's how you do a performance and to have all of that taken away. It's strange. It was a very weird experience, because once we go inside the bank, I'm masked for pretty much the rest of the movie...You've got these fantastic scenes with people like Denzel Washington and Jodie Foster and you've got the mask on. It's very weird for them to act with as well, because they can't see the eyes. It was odd."

You can check out my review of Inside Man, but I think the hardest challenge for Owen was that accent, in the past he's found it very hard and not pulled it off well, this was much better but still...