Amy Winehouse performs “Rehab” for South African civil rights leader Nelson Mandela.

Amy Winehouse performed during the 46664 concert in London’s Hyde Park on Friday. The event, hosted by Will Smith and Jada Pinkett-Smith, is in celebration of Nelson Mandela’s 90th birthday. Here are some pictures of Amy at the Mandela Concert.

“She came out in her very high heels and looked almost nervous in front of the crowd,” the BBC reports. “As she sang ‘Rehab’ you couldn’t help but think she looked a bit… vacant.”

“She perked right up when she began belting out ‘Valerie.’ Seemingly more comfortable with her surroundings, there was more animation – arm and hand movements, sly smiles and she even teetered out onto the stage in the middle of the crowd to finish her song.”