Robbie Williams in rehab

Robbie Williams has been admitted into rehab for treatment for his dependency on prescription drugs, his spokeswoman said today.

The former Take That star, who is 33 today, has entered a clinic in the US.

His spokeswoman Bryony Watts said: "Robbie Williams has today been admitted into a treatment centre in America for his dependency on prescription drugs.

"There will be no further comment on this matter."

The star has constantly battled with his demons, entering rehab for addiction to drink and drugs after boyband Take That split.

Williams, who now lives in Los Angeles, had mixed reviews for his latest album Rudebox.

Today's news comes after model Lisa D'Amato revealed that the pop heartthrob was taking antidepressants and was plagued with worries about his image.

"It was clear he was struggling with his mind. He doesn't drink, but he needs antidepressants to get him through the day. A lot of the time he seemed on edge," she said in a recent interview in the News of the World.

"He would light up a cigarette, take a few drags and then put it out and light another straight away."

She said that even in his sleep the singer was not at peace, adding: "When he started shaking I would gently lift him into my arms and rubbed his arms and legs until he stopped.

"He didn't wake up, but it seemed to calm him down.

"He was very affected about what people thought about his music. He really took things to heart."

The Angels star quit Take That in 1995, after frequent rows with the rest of the band.

His cheeky-chappy image disappeared as he put on weight while he binged on drugs and alcohol.

But after entering rehab, Williams became one of the UK's most successful solo artists with anthems including Angels, Millennium and Rock DJ.

Since parting ways with co-songwriter Guy Chambers, the singer's musical reputation has taken a battering.

While Take That have reformed to huge success, securing number ones in both the album and singles chart, the Stoke-on-Trent-born star has seen his profile slip.