George Clooney was an "adulterer" in second grade.

The 50-year-old confirmed bachelor has dated some of the most beautiful women in the world but has maintained that he will never tie the knot again.

In an interview with James Lipton for The Actor's Studio, the Oscar-nominee claims that he cheated on his girlfriends when he was just seven years old.

"I thought it meant acting like an adult, I didn't know what the hell it meant," the Hollywood heartthrob laughed.

George is also known for being a practical joker and is insistent on playing pranks on his movie sets.

"I am a big believer in making sets fun," he smirked. "I have done some horrible things to people. Truly, truly horrible."

Although George is close friends with fellow actor Brad Pitt, the pair are always up for playing jokes on each other and he can't wait to shock the Moneyball star with his latest idea.

"I am working on one right now for Brad Pitt, it might end his career," George said.

"I owe him, so I'm working it. I've been working on it for two years. I just let him sit. I am not going to let you know what it is, but just know, I got him," George said with a straight face.

However, the suave screen icon also readily laughs at himself, including about his films that have not set the box office alight.

"Coming off of Batman & Robin I suddenly realised I was going to have to pick better projects," he told the audience.