Backstreet's back ... in Nashville.

Not only are Florida Georgia Line flaunting some new No. 1 songs at 2018 CMA Fest, but two of their pop collaborators — the Backstreet Boys and Bebe Rexha — joined the duo in celebrating.

Hosting the party at FGL House on Saturday (June 9), FGL's Brian Kelley and Tyler Hubbard toasted to their No. 1 Billboard singles "H.O.L.Y.," "May We All" and "God, Your Mama and Me" (featuring the Backstreet Boys) from their platinum-certified 2016 Dig Your Roots album.

As icing on the cake, the duo also celebrated their uber pop-infused country No. 1 duet with Bebe Rexha, "Meant to Be." The song is so hot, it also peaked at No. 2 on the all-genre Billboard Hot 100 chart. Keep in mind, FGL's "Cruise" — the best-selling country digital single of all-time — peaked at No. 4 on the Billboard Hot 100 in 2013.

Could This Be the Next FGL Collab?

Riding on their wave of collaborative success, it's fair to ask: who's the next collab for FGL? At Taste of Country Music Festival a day prior, the duo admitted they're looking forward to more crossover hits and would love to work with Bruno Mars or Rihanna. FGL recently released two new tracks —  "Simple" and "Colorado" — and perform Sunday night at CMA Fest at Nissan Stadium. Will their in-town collaborators stick around an extra day to join them?

Related: At the No. 1 party, members of the Backstreet Boys also confirmed they've finished three studio songs during their Nashville trip for their forthcoming album, but no word on if those songs have features from any country stars.

See Photos from FGL's set at the 2018 Taste of Country Music Festival