Rob Lowe. Photo by Richard Shotwell/Invision/AP

Rob Lowe developed a passion for health and fitness in order to beat his battle with addiction.

The 54-year-old actor has been sober since he was 26, and says he managed to stay away from his vices by channelling his addictive behaviour into health and fitness, including falling in love with surfing.

He said: "[Health and fitness] became an outlet for all of the tension, stresses, compulsivity. I funnelled the addiction, frankly, into that.

"[With surfing,] you're always chasing a high that you're probably not going to ever repeat. Conditions change, so no waves ever just stay the same. Nothing can ever stay the same. Nothing."

The former 'Parks and Recreation' star is unconventional about his workouts, and although most people blast their favourite gym playlist whilst they exercise, Rob prefers to put himself in a state of "forced mental solitude".

He added: "I like the forced mental solitude of it. Inevitably, it will force you to start working through things you're not going to if you're listening to Jay-Z."

And Rob - who has 26-year-old son Matthew, and 24-year-old son John with his wife Sheryl Berkoff - also insists he's become "vain as f**k" when it comes to his body, but believes all men are vain even if they deny it.

Speaking to Men's Health magazine's February issue, the 'West Wing' star said: "Men deny having vanity - that's the greatest vanity. Not me. I'm vain as f**k."

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Father son workout to start the day! @johnnylowe

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Meanwhile, Rob previously claimed the "gift of alcoholism" has given him a better life, because his subsequent recovery has helped improve his health and wellbeing, as well as letting him develop traits including "integrity" and "gratitude".

He said: "Being in recovery has given me everything of value that I have in my life. Integrity, honesty, fearlessness, faith, a relationship with God, and most of all gratitude. It's given me a beautiful family and an amazing career. I'm under no illusions where I would be without the gift of alcoholism and the chance to recover from it."