Brad Pitt has revealed his new moustache is for his role in By The Sea.

The World War Z star showed off his facial hair at the UK premiere of Fury, which closed the BFI London Film Festival.

"Yes, this is for the film. This was not a fashion choice," he joked on the red carpet.

Family drama By The Sea will also star Brad's wife Angelina Jolie, who is the film's writer and director.

The father-of-six, who married Angelina in France in August, said the couple shot the film in Malta on their honeymoon.

"We like extremes - we like to be a little here, a little there and it all seems to balance out somehow," he added.

Brad plays tough army sergeant Wardaddy in David Ayer's World War II film, which also stars Shia LaBeouf, Logan Lerman, Michael Pena and Jon Bernthal.

The cast bonded over bootcamp and fighting sessions - and the Hollywood star knew just who to stay away from.

"Shia's got this really swirly left upper cut. You've got to stay away from that one," he revealed. "And Bernthal's just a boxer. You've got to stay on the outside. Once you step inside, you're done. So you gotta stay outside and kick him in the nuts."

Fury is in cinemas now.