text: katherine mcphee's song from last night's american idol? does anyone know the title and artist of the song that katherine mcphee sang on 4/18 on american idol? the song is called "someone to watch over me".  technically, all of last night's songs were sung by rod stewart.  however, this is because he re-did it on one of his recent albums.  the song was originally written by george and ira gershwin, as part of the musical "crazy for you".  over time, it has been sung by many artists, including frank sinatra and sting.