Florida Georgia Line and John Legend teamed up during the 2017 Billboard Music Awards on Sunday night (May 21) to perform each other's hits. Together, the country duo and the R&B singer-songwriter sang FGL's "H.O.L.Y." and Legend's "Surefire."

Accompanying himself on piano, Legend opened the performance by singing "Surefire" alone on a darkened stage. As he segued into "H.O.L.Y.," Florida Georgia Line's Brian Kelley and Tyler Hubbard appeared onstage to cheers from the crowd. Kelley and Hubbard took the song's first verse and chorus then traded lines and harmonized with Legend throughout the rest of the tune.

"We got to write a song together in LA [recently]," Hubbard said of Legend on the 2017 Billboard Music Awards red carpet. "He's a great dude ... so it just kind of organically worked out. We've been big fans of him for years and respect him a lot."

In May of 2016, "H.O.L.Y." became a No. 1 hit for Florida Georgia Line; the song vaulted from No. 39 to No. 1 on Billboard‘s Hot Country Songs chart in a single week -- the third-greatest leap to the top spot in that chart's history. "Surefire," meanwhile, is Legend's newest single, from his 2016 album Darkness and Light.

Florida Georgia Line are nominated for five trophies at the 2017 Billboard Music Awards: Top Duo / Group, Top Country Artist, Top Country Album, Top Country Song and Top Country Collaboration. Other nominated country acts include Luke Bryan (the all-genre Billboard Chart Achievement Award, Top Country Tour), Chris Stapleton (Top Country Artist, Top Country Album) and Little Big Town (Top Country Song), among others.

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