The rapper won the Mercury with debut album Speech
Therapy in September.
Mercury winner Speech Debelle was booed by Take That fans as she tried to rap one of their songs at a London event in honour of the group.
The rapper was one of a host of stars performing at the launch of the SingStar Take That video game.
Debelle chose to rap her way through the 1993 hit single Pray, leading to boos from some of the 500-strong crowd.
She was also criticised by host James Corden, who said "anyone can rap", before launching into a rap of his own.
Take That were also present at the event performing some of their hits.
Singers Lily Allen, Paloma Faith and Rachel Stevens, model Kate Moss, and Pixie Geldof were also at the party.
Amy Winehouse's goddaughter, Dionne Bromfield, performed her version of Patience.
The party was held in aid of Body & Soul, a charity dedicated to supporting children, teenagers and families across the UK who are living with or are closely affected by HIV.
It was originally scheduled for October but was postponed following the death of Barlow's father.
Debelle's performance came days after she revealed to BBC 6 Music that she was quitting her record label, blaming them for poor sales following her Mercury win in September.