Backstreet Boys Join Florida Georgia Line to Declare 'Backstreet's Back' at iHeartRadio Music Festival

Christopher Polk/Getty Images for iHeartMedia
Backstreet Boys perform with Florida Georgia Line at the 2016 iHeartRadio Music Festival at T-Mobile Arena on Sept. 24, 2016 in Las Vegas.

BSB get some Las Vegas practice in before starting their Planet Hollywood residency in 2017.

The Backstreet Boys just announced their new Planet Hollywood residency in Las Vegas on Friday, and the next day, they were already making themselves at home in Sin City. The boy banders made a surprise appearance with Florida Georgia Line at the iHeartRadio Music Festival on Saturday night (Sept. 24) at T-Mobile Arena to perform "Everybody (Backstreet's Back)."

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The two groups already have some history: FGL and BSB teamed up for the song "God, Your Mama, and Me" from Florida Georgia Line's most recent album, Dig Your Roots. But on Saturday night, they teamed up for the 1997 Backstreet classic.

Watch a clip below:

BSB returned after Florida Georgia Line left the stage with their own mini-set, including "I Want It That Way," "As Long as You Love Me" and "Larger Than Life" -- also the name of their upcoming residency.

Florida Georgia Line have clearly been fans of the Boys for awhile. Back in March, they covered "Everybody" at a show, with Brian Kelley revealing onstage that his first concert was Backstreet Boys and Tyler Hubbard chimed in that they were his first album. Watch the lovefest below: