Fifth Harmony Fan Gets A Major Studio Surprise -- And Some Pretty Famous Backup Singers

When Shazam Top 20 invited Fifth Harmony fan Caitlin to the studio, she had no idea she'd be singing with some special guests.

Caitlin started singing the group's hit "Sledgehammer" solo, but when the chorus dropped the girls of Fifth Harmony joined in after being unveiled in the room next door. The singers cheered her on for the rest of the song before they all got in on some serious hug action.

Best studio surprise ever.

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