LONDON - British pop star Robbie Williams has been admitted to a rehabilitation center in the United States where he will undergo treatment for prescription drug addiction, his agent said on Tuesday.

Williams, who celebrates his 33rd birthday on Tuesday, is one of Europe's most successful entertainers who rose to fame as a member of the hit boy band Take That before forging a successful solo career in the past decade.

"Robbie Williams has today been admitted into a treatment center in America for his dependency on prescription drugs," his public relations agent in London said. "There will be no further comment on this matter."

Williams, who was born in Britain and now has a home in Los Angeles, has a history of struggling with addictions and was treated for drug and alcohol dependency after Take That split up in 1995.

His latest album, Rudebox, has had mixed reviews in Britain and sold just under a million copies in the United States.