The singer will join Jay-Z on stage to sing 'Empire State Of Mind' at the event, which is held in London on February 16.
"Alicia is a fantastic addition to the show. I can't wait to see her and Jay-Z perform one of the biggest songs of the year," Brits Committee chairman Ged Doherty said.
Lady GaGa, JLS, Robbie Williams, Chery Cole and Lily Allen have also been confirmed to perform at the ceremony.
According to recent reports, Jay-Z's wife Beyoncé will also join Lady GaGa on stage to sing their collaboration 'Telephone'.
Keys's third album The Element Of Freedom climbed to the top of the charts for the first time last week.