Spears takes to the stage

Britney Spears performed before a live audience for the first time in three years Tuesday, appearing as part of a mysterious group billed as the M+M’s that played a sold-out show at San Diego’s House of Blues.

Over the course of a 16-minute mini-set, Spears danced and reportedly lip-synced several of her most familiar material songs, including “Oops! ... I Did It Again” and “Toxic,” accompanied by a quartet of female back-up dancers. The M+M’s are scheduled to perform at the West Hollywood House of Blues tonight. Spears’ participation remains a question mark.