Leon "Roccstar" Youngblood Jr. is an American music producer, songwriter, recording artist and rapper. Youngblood has written and produced songs for artists such as Chris Brown, Post Malone, Usher, Rita Ora, Fergie, Prince Royce, Kendrick Lamar, J.Lo, and Melissa Etheridge.

X is the sixth studio album by American singer Chris Brown. It was released on September 16, 2014, by CBE Entertainment and RCA Records. The album serves as the follow-up to his fifth album Fortune (2012). Brown for the album worked with several producers, including RoccStar, Danja, Nic Nac, Diplo and others. The album also features guest appearances by various urban artists, including Kendrick Lamar, R. Kelly, Akon, Nicki Minaj, Usher, Trey Songz, Tyga, Rick Ross, Brandy, Lil Wayne, Jhené Aiko and Aaliyah.