Hot on the heels of Miley Cyrus, Sam Smith is the latest celebrity to join James Corden for a spot of Carpool Karaoke. As you'd expect, the pair take great joy in singing along to some of Sam's biggest hits, including "By Your Side" and "Money on my Mind", before talk turns to Sam's obsession with a certain girl band. "I'm a harmonizer!" he admits, before bursting into Fifth Harmony's "Work From Home". Things really take a turn when James puts in a phone call and invites some special guests along for the ride. Watch Sam's reaction, plus so much more, in the video.