*NSYNC Officially Drops New Song 'Better Place,' Fans Go Nuts Over 'Trolls' Track

*NSYNC's brand-new song, "Better Place," is officially out for the world to enjoy ... and fans are going wild over the first track heard from the group in over 20 years.

The boy band's song officially dropped online Thursday, made for the flick, "Trolls Band Together." As we reported, a teaser of the song debuted a couple of weeks ago, but folks can get the full experience now ... and the consensus is that it's an absolute banger.

Fans have been praising the track since it dropped ... one said it "gets better with each listen," and another said they're loving every second of it -- including "JC's voice esp the adlibs  😍😍😍."

Some pointed out a piece of the song that isn't sitting right with them, though -- the track is credited as *NSYNC and Justin Timberlake.

Obviously, Justin -- one of the stars of the "Trolls" franchise -- is a part of *NSYNC, but fans saw the separation as a sign that JT wasn't back with them.

A source with direct knowledge tells TMZ ... the reason Justin was credited separately is strictly for algorithm purposes. We're told because Justin's the only one who has released hits in the era of streaming, it was decided to put his name next to the group.

Sources say it was Justin's idea to have JC Chasez, Lance Bass, Chris Kirkpatrick, and Joey Fatone on the song with him ... as made clear from the BTS video of them having a blast back in the studio together.

Remember, the group doesn't have plans to go on tour, do a residency, or a new album after the "Trolls" song ... but we're told if the gang decides to record a full album, it would have a whole new sound.

Do you like *NSYNC's first new song in over 20 years? Vote below.