Lady Gaga, who is back in New York City to put the final touches on her highly-anticipated new album, stopped by Gramercy Park Hotel's Rose Bar on Tuesday night for a surprise performance with her friend Brian Newman and his band. Dressed down in an all-black YSL outfit, Mother Monster took the stage to sing some of her favorite jazz standards, including "La Vie En Rose" and "I Can't Give You Anything But Love." Watch below!