In this collaboration of epic proportions, Alicia Keys teamed up with Beyonce for "Put It in a Love Song." With a simple beat, powerhouse vocals and an amazing feel, this song was the hit that never was. The duo recorded a music video for the song in Brazil, but unfortunately the visual never met the light of day. Maybe one day they'll unleash it from their secret vault... we hope.
(Photos from Left to Right: Anthony Harvey/PictureGroup, Michelly Rall/Getty Images for Live Earth Events)