The Ocean's Eleven star is a notorious practical joker, and one of his favourite wind-ups is to use his specially-made stationery bonded with Brad Pitt's name to write to stars 'on behalf' of his actor pal.

However, he is now frightened he has taken the joke too far and has penned a note to an unidentified victim which is so serious he could be in trouble with the cops - and he's hoping his lawyer wife Amal will help to bail him out.

Clooney tells U.K. talk show host Graham Norton, "I have sent letters to lots and lots of people from Brad and I don't tell either of them what I have done for a year or two and they are like, 'Are you kidding me?' I'm doing one now that I can't tell you about but in a year you are going to hear I've been arrested - I'm not kidding because I think I've crossed the line. It's exciting. But, I have a wife, she's a barrister, I'll be fine!"