British pop star Robbie Williams checked into a U.S. rehab center for prescription drug addiction. Williams is no stranger to rehab, having been treated for drug addiction in the '90s. Today is his 33rd birthday.

A rep for Williams said, "Robbie Williams has today been admitted to a treatment center in America for his dependency on prescription drugs. There will be no further comment on this matter."

From drug and alcohol addiction to anger management, Williams is the latest in a laundry list of stars to announce that they were seeking professional help. In the past few months, Lindsay Lohan, Miss USA Tara Conner, Mike Tyson and "Grey's Anatomy's" Isaiah Washington have all checked into rehab.

While a huge star overseas, Williams has not been able to match that level of fame in the USA.