For the second night in a row, Justin Timberlake appeared on Jimmy Fallon's late-night talk show to promote his upcoming record 'The 20/20 Experience.' Instead of performing a comedic 'History of Rap' medley, as JT has done many times in the past, the singer opted for a ragtime barbershop quartet version of 'SexyBack.'

In this case, it was a barbershop quintet consisting of Timberlake, Fallon and three others. The guys took sexy way, way back with old-timey striped suits and hats and harmonies that presented the song in an entirely different way. Surely Timbaland never imagined this when he helped JT write the song!

Timberlake also performed the soulful 'Mirrors' with a large live band behind him. They cut the 8-minute song down to about six for the show but kept in the tender falsetto section that plays out the track.

Justin will appear on Fallon all week, so stay tuned for a lot more hilarity and musical goodness. A night earlier, Timberlake performed 'Pusher Love Girl.' 'The 20/20 Experience' hits stores next Tuesday, March 19, with bonus tracks available on the Target edition.

Watch Justin Timberlake Perform 'Mirrors'