Lance Bass' Mom Turned Down First Offer for Him to Join *NSYNC

When *NSYNC came calling, Lance Bass wanted to take the offer -- no strings attached -- but his mom had other ideas.

The singer tells the story in the new Joey Fatone-produced documentary "Boy Band Confidential" ... explaining he got a call out of the blue to audition for the group when he was 16 and living in small-town Mississippi.

While clearly the opportunity of a lifetime, Bass says his mom seemed skeptical ... and told manager Lou Pearlman, Justin Timberlake, and Justin's mom Lynn, they may need a new band member -- but it wasn't gonna be her son.

That could've been the end of the story ... but, thankfully, his mom got another call -- and she agreed to take Lance to Orlando, Florida to audition.

Bass says he felt like a fraud during the audition ... the imposter syndrome hit hard while singing and dancing with the other ultra-talented dudes -- plus, he wasn't out of the closet yet, and that compounded the feelings.

Obviously, the audition worked out ... the band landed 9 Grammy nods and has sold more than 70 million records worldwide.

"Boy Band Confidential" is full of interviews like this ... with stars like Nick Lachey, Jeff Timmons, and Joey Fatone himself telling their stories ... and diving into the dark side of the boy band craze of the 1990s and early 2000s.