Pink - Who Knew

"Who Knew" is a song by American singer Pink from her fourth studio album, I'm Not Dead (2006). Written by Pink, Max Martin and Lukasz "Dr. Luke" Gottwald, the song was originally released on May 8, 2006, by the LaFace label to radio as the album's second single, but was only a moderate success. The song saw more success upon its re-release in the United States in June 2007, thanks in large part to the success of U + Ur Hand. Musically, "Who Knew" is a pop song. Lyrically, it expresses regret at the untimely loss of Pink's good friend.