Organisers are expecting Amy Winehouse to perform at V Festival

A spokesman for the 23-year-old said: "She is resting under doctor's orders."

He declined to comment on newspaper reports that the star was going to rehab for treatment for drug problems.

Despite cancelling several concerts, including an appearance at two Rolling Stones gigs, she is still expected to perform at this weekend's V Festivals.

A V Festival spokesman said: "We have not been informed by either Amy's record company or her management that she won't be appearing at this year's festival.

"Unless otherwise informed, organisers are expecting her to appear as planned."

In the past few weeks, Winehouse has pulled out of the T in the Park festival - also citing "exhaustion" - and Liverpool's Summer Pops event.

Despite the cancellations, the star has been frequently photographed in pubs when she had been expected to appear on stage.

The singer, whose hit single Rehab won best song at the Mojo awards in June, recently married her husband, Blake Fielder-Civil in a secret ceremony in Miami.

Last week she received three nominations at the MTV Video Music Awards, including Female Artist of the Year.