The British star was due to perform alongside the Grammy-winning singer at her 'Keep A Child Alive Ball, but had to drop out after being struck down with a tooth infection.
"I'm very disappointed. George Michael bailed on us. I think he said he had trouble parking or something," Alicia joked on stage, before launching into Freedom.
Our celebrity reporter Scott Wimsett was there to get the inside track on the celebrity arrivals.
The talented and eccentric Paloma Faith, one of the evening's performers, dazzled in a gold Vivienne Westwood gown and a Victoria Grant cap to match.
Actor Jesse Metcalfe was another famous face showing his support: "It's a great charity, I know [Alicia's] been involved with it since the beginning of her career. I know it's going to be a great night," he said.
Rapper Tinie Tempah, actor Dougray Scott, singer Shingai Shoniwa and Alicia herself all took time out to chat to Scott.
"You don't have to do things like this and her life is pretty demanding as it is.
"It's nice when someone takes time out of their busy schedule to give back," said Tinie.
New mum Alicia, stunning in a Givenchy black and white gown and was accompanied by her husband, producer Swizz Beatz, throughout the evening.
The auction - which included items like a portrait of Michael Jackson by Los Angeles pop artist Thierry Guetta and a day-long studio session with producer Mark Ronson - raised £177,000 for African and Indian children affected by HIV/AIDS.