Amy Winehouse, seen here last week in London the day she entered rehab, has been put on a drip in hospital after it was revealed the singer has become dangerously dehydrated

The singer, 24, who was recently shamed in a video that apparently showed her smoking crack cocaine, was smuggled into a Harley Street clinic on Wednesday for treatment.

A source close to the London Clinic, which is near the Capio Nightingale Hospital in Marylebone, where Winehouse is undergoing rehab, told The Sun: "Amy was looking very pale and thin.

"She looked ropey and exhausted. Let's hope she hasn't taken a turn for the worse."

Her father, Mitch, 57, has said she is suffering "horrific" withdrawal symptoms. He said yesterday that she was "making progress" but that it would take a "long time".

Winehouse went into rehab on January 24, supposedly to get well enough to attend the Grammy Awards in Los Angeles on February 10, for which she is nominated in six categories. But her father said he did not think she was ready.

He said: "I'm not sure the Grammys are going to happen. I don't want her to go, it might be a bit too soon for her. She's not well - that's why she's in rehab."

A spokesman for Winehouse said she had been taken to the clinic to be put on a drip.

He said: "It was all normal and routine and part of Amy's ongoing treatment.

"She went on a drip to rehydrate, which is a good thing - it means she is getting through her recovery.

"Amy went to the clinic because the hospital doesn't have the facilities."