Would lke to find out name of song and performer in the movie "two weeks notice" played in near last scene?

i caught the ending of the movie Two weeks notice, with hugh grant and sandra bullock. the scene where they were at a big party, with donald trump and big shots like him, were dressed in costume or tuxedos and gowns with some sillyelaboration. well there was a young lady playing the piano and singing a song, and i was hoping that someone can give me the name of that song and the performers name. I would like to find it in the store , thank you. hope this is enough information.