Matt Damon "didn't know" he could grow a moustache.

The actor is currently sporting facial hair for his role in the new Coen Brothers movie 'True Grit', which he is about to start shooting, and admits he is enjoying the reactions people have given his new look while promoting his current project 'Green Zone'.

He said: "I didn't know I could grow one. Unfortunately, that means having to do a press junket with a moustache. My wife Lucy went online and saw. 'What the f**k is that thing on his lip?' "

The 'Invictus' star lives in New York with his wife, stepdaughter Alexia, 11, and daughters Isabella, three, and 17-month-old Gia and claims they are able to live a "normal" life in the city.

He added to the USA Today newspaper: "They're all thriving. That's why we're so excited about it here.

"We're not leaving. Nobody bothers me. The younger ones are not aware of any of the celebrity stuff. We walk to school every morning. We play in the park. It feels like a normal life."