Amy Winehouse will remain in hospital "as long as possible", her father has said.
The singer was taken to the London Clinic, near Harley Street, after fainting at home on Monday. She was originally expected to be discharged on Tuesday but today appeared likely to stay for some time.
"Amy is doing fine, she is staying in as long as possible," said her father Mitch.
Her spokesman said: "She'll stay for as long as they can find out what's wrong with her. I don't know what's wrong with her and the doctors don't seem to.
"There are various possibilities. It's probably something to do with her ongoing treatment."