LONDON - Amy Winehouse has packed a punch at the Glastonbury music festival.
The troubled singer took the stage Saturday, climbing down into the pit and scuffling briefly with a reveller.
It was unclear what sparked the altercation at the large music and performing arts festival in southwest England, but some witnesses said a fan tried to grab Winehouse.
Performing in front of 80,000 fans, Winehouse sang for about an hour.
She shocked fans on Friday by performing at a special birthday concert for Nelson Mandela. The performance came just days after she had been admitted to hospital for tests.
Her father says Winehouse has developed emphysema from smoking cigarettes and crack cocaine, although her spokeswoman has said Winehouse only has pre-emphysema symptoms.
