Backstreet Boys & 'NSYNC McLean & Fatone Duet for 40th Bday ... What Rivalry??!!

1/30/2017 2:36 PM PST

Backstreet Boy A.J. McLean Duets with 'NSYNC's Joey Fatone for 40th Birthday

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If A.J. McLean and Joey Fatone can wave the boy band white flag and come together onstage ... then maybe there's hope for America too.

The awesome duet went down Saturday night during Joey's 40th birthday bash at Ora nightclub in Miami. The former pop rivals decided to serenade the crowd with the Backstreet Boys hit, "I Want It That Way."

You'd think they'd do an 'NSYNC tune ... it was Joey's night after all, but the crowd ate it up, anyway.

If BsB ever needs a fill-in baritone, holla at Fatone! He's available.