Lupe Fiasco, "Old School Love" (2013)
Just as Sheeran's opening slot on Taylor Swift's Red tour was breaking him to U.S. audiences, he surfaced by singing the hook on Chicago rapper Lupe Fiasco's nostalgic single "Old School Love." Though it seems like an unlikely collab, Sheeran had already collaborated with British hip-hop acts Wretch 23 and Devlin. "[Lupe] just gave me about seven beats and said write choruses to all of these," Sheeran said at the time, calling himself "a massive Lupe Fiasco fan." But with Ed lending his easy, mild-tempered feel, you'd think the singer and the MC were in the same room.