Watch Justin Timberlake Sing a Barbershop Version of 'SexyBack' on 'Late Night' [Video]

Justin Timberlake is bringing barbershop back!

On the second night of his weeklong residency on "Late Night With Jimmy Fallon," the singer and host teamed up with barbershop singers the Ragtime Gals to do a harmonious, a cappella version of his classic hit "SexyBack."

[Related: Justin Timberlake Does Milli Vanilli on 'Late Night']

It was all at the behest of a fan who'd submitted the request to the "Late Night" suggestion box.

Timberlake will be on "Late Night" all week, performing songs from his new album, "The 20/20 Experience."