Brad Pitt knows whether his 'Once Upon A Time In America' character Cliff Booth killed his wife.

Brad Pitt

Brad Pitt

In the movie, there is speculation that Cliff murdered his spouse Billie, played by Rebecca Gayheart but it is never confirmed and Brad revealed he has no plans to tell people what really happened.

The movie shows the couple drinking heavily on a boat out at sea, with Cliff pointing a harpoon gun at his wife but it does not give a definitive answer and Brad told The Los Angeles Times: "That, I will never tell."

Brad, 55, added that he would prefer for the audience to make up their own minds about his character, explaining: "So why spoil that?"

Meanwhile, director Quentin Tarantino recently revealed that Cliff was a Green Beret, explaining that the stuntman's training is what helped him to beat legendary fighter Bruce Lee in a physical confrontation in the movie.

He said: "The reality of the situation is this: Cliff is a Green Beret. He has killed many men in World War II in hand-to-hand combat. What Bruce Lee is talking about in the whole thing is that he admires warriors. He admires combat, and boxing is a closer approximation of combat as a sport. Cliff is not part of the sport that is like combat, he is a warrior. He is a combat person."