Colin Farrell may have struggled with hard drugs in his younger days, but he never killed a guy.

Farrell revealed on "The Tonight Show Starring Jimmy Fallon" that as a teenager, he was brought in for questioning as a suspect in an attempted murder. He spent six hours in a Sydney, Australia police station trying to convince authorities that he was not the man in a pencil sketch.

"I saw a photofit of the guy that actually did the crime and it looked remarkably like me and for a second, because I had had a blackout that night I wondered, 'Could I have done such a thing?'" he said while trying to fool Fallon and his "True Detective" co-star Vince Vaughn in a game called "True Confessions."

Playing on the name of the HBO series, "True Confessions" is a game where two contestants interrogate the third and try to prove whether he's telling the truth or a lie based on a confession in one of two sealed envelopes.

Fallon and Vaughn guessed correctly that Farrell was telling the truth and the "Total Recall" star admitted the experience was "very" uncomfortable.

"I was supposed to bring my mother to the airport - I was in Sydney, Australia. I was called in by the cops and they showed me a photofit of a pencil sketch of the guy that had attempted to murder this other gentlemen. [He'd] beat him up and left him in his own apartment and set the apartment on fire and split, thereby leaving the guy to burn to death. It was me. They said, 'What do you think about that picture?' And I went, 'I think I'm in trouble.'"

Farrell continued, "It was terrifying. I was there for about six hours and then thankfully, a friend of mine had kept a journal and that particular night at that particular time, we were at a party on the other side of town doing ecstasy."

Catch the complete game of "True Confessions" in the video below: