VIDEO : Mary J. Blige, Jason Derulo, Britney Spears Among Artists to Release a Song for Orlando Mass

They've recorded a heartbreaking charity single that will benefit victims of the Orlando nightclub massacre. It was dreamed up by songwriter Justin Tranter, who co-wrote Justin Bieber's song "Sorry," among other massive hits, and has been raising money for LGBT causes since he was 14. The single is available to purchase exclusively on iTunes, and proceeds from the sale will benefit the Equality Florida Pulse Victims Fund, the GLBT Community Center of Central Florida, and GLAAD.