The singer Robbie Williams has checked into rehab on his 33rd birthday.

The former Take That star’s spokeswoman, Bryony Watts, confirmed that he has been admitted to a clinic to deal with an addiction to prescription medications.

In December 2005 Williams successfully sued the People and the Daily Star and over allegations he was secretly gay.

He won an apology and undisclosed damages from MGN Ltd and Northern Shell plc.

William’s barrister, Tom Shields QC, told the court that the singer “is not, and has never been, homosexual.”

The court heard that the People’s front page story, “Robbie’s secret gay lover” insinuated that the star intended to mislead the public by claiming to be straight.

Following the award of damages, campaigner Peter Tatchell claimed in a column for PinkNews.co.uk that:

“the legal action has created the impression he thinks it is shameful to be gay.

“If he sees nothing wrong with being gay, why did he sue for libel?”

Ben Summerskill, Chief Executive of the gay rights group Stonewall warned that William’s latest outburst “risks appearing hypocritical.”

“I know Robbie’s explanation for mounting the case was that the tabloids made lurid suggestions suggesting that he had gay sex in public toilet.

“Clearly, when he launched his case, he wasn’t very mindful of the damage that it does to suggest that there’s something wrong with being gay.”

Williams is close friends with Elton John, and will reportedly be doing at “full monty” strip for the out gay singer on his 50th birthday.

John will be celebrating the landmark birthday on 25th March with a performance for friends and celebrities at New York’s Madison Square Garden.