A boy band battle between the Backstreet Boys and *NSYNC might finally go down ... but sorry, music heads -- if BSB has it their way, it won't be with microphones.

Nick Carter and Brian Littrell told TMZ Sports this week they actually want to take on Justin Timberlake and Co. in a golf match! Instagram / @nickcarter

The guys threw down the challenge while they were playing a round at Pebble Beach ... during a brief break from their tour at the Sphere in Las Vegas.

"You hear it first on TMZ," Littrell said. "It's going to be 'Boy Band Mania Golf Tournament!'

"Yeah, let's go," Carter added. "We're challenging *NSYNC right now to a five-on-five!" Getty

Unclear how each of the bandmates stack up against one another ... but at the very least, Timberlake vs. Littrell sho

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