Colin Farrell has spoken of his hellraising days as an era that is over, and explained how they were a reaction to his quick rise to fame.

“It was mad, and it defied any contemplation,” he said, in a revealing interview with the London Times on Friday. “And I wasn’t at a stage where I wanted to contemplate it. I just enjoyed it as it came.”

This enjoyment took the form of indulging in excesses and a rock ‘n roll lifestyle. For Farrell, his behaviour was connected with identity.

“I wanted to show that I was proud of my Irishness,” he confessed in the interview. “And I kind of felt I was representing that side of me.

“But I was doing it in the most clichéd way possible,” he added.

Farrell, who grew up in Dublin and was expelled from at least one school, said he wanted to be famous right from the start.

“Fame was something that seemed incredibly exotic,” he said. “It represented the ultimate kind of status. But it eventually became one of those ‘be careful what you wish for’ things.”

He said that Heath Ledger’s death had made him realize what could have happened.

“This could’ve been me. I wouldn’t describe it as survivor’s guilt, but yes, that came into it a little bit. It makes you ask some questions about yourself.”

As well as struggling to achieve a balanced lifestyle, he has struggled with the issue of privacy, so much so that even when he was a spokesman for the Special Olympics in 2003 he did not want to reveal his older son, James, has a disorder called Angelman Syndrome.

“At the time I felt like I really wanted to speak about my son, not as a famous person or any of that shite, but as a proud father and someone who wanted to speak about the adversities he’d faced and combated,” he recalled. “And that’s when it became a case of, ‘F***! Who am I protecting here with this privacy?’ ”

Now, Farrell, who is 33, seems to have overcome his growing pains. He lives in LA with Alicja Bachleda, the mother of his younger son, Henry, whom he met while filming the movie, “Ondine.” He’s a reformed character, who hasn’t taken drugs in three years, or alcohol in two.

Yet he’s also determined not to have regrets. “Look,” he told the Times reporter, “The ins and outs of what I’ve been through, even when it comes to rehab, is not a sad story. None of it is a sad story. I had a great time and some amazing memories and lots of good stuff that I’ve forgotten.”

Farrell: a changed man