Winehouse Still in the Ward

Singer remains hospitalized in London while doctors determine cause of her fainting spell

Amy Winehouse appears to be just what the doctor ordered.

The troubled singer remained hospitalized overnight after suffering a mysterious fainting spell at her London home Monday and will continue to undergo tests today to determine the cause of her brief blackout.

"She's staying there for the time being," her London rep said. "They are still not quite sure what happened, and the tests were inconclusive."

"She seems to be fine in herself, but they are taking their time to be sure."

The 24-year-old "Rehab" singer was rushed to the London Clinic by her father, Mitch, yesterday afternoon as a "precaution" following her collapse, despite the fact the songbird was said to have "quickly recovered" after fainting.

Her manager's assistant was with her at the time and prevented Winehouse from falling.

She is expected to perform as planned at Nelson Mandela's 90th birthday celebration concert in London June 27.