Matthew McConaughey has revealed that he was "molested" as a teenager. He also says he was "blackmailed" into losing his virginity at the age of 15.

This is the first time Matthew McConaughey has publicly spoken about the sexual assault.

The actor opens up in his new memoir 'Greenlights'.

The title reflects how he sees his life as going through events he describes as green, yellow or red lights, which cause him to movie forward, pause or stop.

In the beginning of the book, he says that his first experience of sex was not consensual.

He writes: "I was blackmailed into having sex for the first time when I was 15. I was certain I was going to hell for the premarital sex.

"Today, I am merely certain that I hope that’s not the case."

Matthew McConaughey also reveals that he was "molested by a man when [he] was 18 while knocked unconscious in the back of a van."

He did not give more details, but the actor continues: "I've never felt like a victim.

"I have a lot of proof that the world is conspiring to make me happy."

The actor will be appearing on this Friday's 'Late Late Show' to talk about 'Greenlights'.