Troubled star Amy Winehouse has attacked a fan outside her London home - after accusing him of pinching her bottom.

The Rehab hitmaker lashed out at the unidentified male fan as he tried to take a photograph of her on Saturday night.

A source tells British newspaper The Sun, "Amy had her bottom pinched and blamed the fan taking her picture.

"She just lashed out and clumped him. He laughed it off."

It was the second time in a week the singer has attacked a fan.

She punched a man for touching her trademark beehive hairdo during her performance at U.K. music festival Glastonbury last weekend.