Colin Farrell feared he was "unhireable" due to his battles with drink and drugs.

The 37-year-old actor claims entering rehab for addiction to recreational drugs and painkillers in December 2005 helped salvage his burgeoning Hollywood career as he worried producers wouldn't want to hire him because of his hard-partying lifestyle.

He told the Metro newspaper: "I wouldn't have been able to maintain my life. The inside of rehab was a must-see for me at that stage. I was in a bad place. I'm sure I was becoming somewhat unhireable."

Following his sobering experience in rehab, the Irish star has gone on to enjoy critical acclaim in movies such as 'Saving Mr. Banks', but he says the greatest joys in his life are his two sons James, 10, and four-year-old Henry.

Quizzed about his approach to parenting, he said: "Be present. Just run up and take it from there. My sons are fairly well behaved ... I don't know if that's a testament to me or them but they're lovely young fellas.

"You try to instill respect, politeness and gratitude for what they have and I just enjoy them immensely."

While he may be one of the most recognizable stars in the world, Colin insists he doesn't care about fame, which he feels is simply a "by-product" of his acting work, but he accepts notoriety is part of his job.

He explained: "It's allowed me to do some amazing things for friends and family and allowed me to care for people in my life that I might have been able to do otherwise. I'm not going to bitch about it."