From Queenpedia.com

Catherine Porter is an American singer, songwriter, and musician. She is a former member of Brian May band and has appeared in several musicals and films. To date, Porter has released one album of solo material, Something Good, in 2002, and has also worked as a backing singer for the likes of Queen, Tony Hadley, Edwin Starr, Kiki Dee, Paul Rogers, Sam Moore, Mel B and Chaka Khan.

She also sang backing vocals on the Queen track Let Me Live.