Woody Harrelson became a vegan to clear up his acne.

The 'No Country for Old Men' actor - who hasn't eaten meat since his 20s and now only eats raw food - says his decision to avoid meat and dairy products has nothing to do with animal rights and actually started when a stranger told him it would improve his complexion.

He told Maxim magazine: "It's been at least 20 years. I used to eat burgers and steak, and I would just be knocked out afterward. I had to give it up.

"The first thing was dairy. I was about 24 years old and I had tons of acne and mucus. I met some random girl on a bus who told me to quit dairy and all those symptoms would go away three days later. By God she was right."

The 48-year-old star is not the only celebrity who has credited veganism - which also prohibits the use of products made from animals, such as leather - with improving their appearance.

Former 'Baywatch' star Pamela Anderson recently revealed she lost weight and toned up thanks to teaming her anti-dairy and meat diet with long walks with her vicar.

She explained: "I've never dieted, but I'm cooking vegan now and I think that helps.

"I walk with my minister in the mornings. I know it's the funniest thing for Pamela Anderson to do, but it's true. I talk about God and walk. It's like a daily Bible study."