*NSYNC Members Interviewed for Justin Timberlake Docuseries

Some of the guys from *NSYNC will be making appearances in Justin Timberlake's upcoming docuseries ... but don't get your hopes up for a boy band reunion ... TMZ has learned.

Sources familiar with the situation tell TMZ ... several members of the iconic boy band sat down for individual interviews backstage at JT's show at The Wiltern in Los Angeles a couple of years ago.

We're told the guys were asked about their time together in *NSYNC, reflecting on their experiences as members of one of the biggest boy bands of all time.

However, our sources say the interviews had nothing to do with a potential reunion or future plans for the group ... and the guys weren't interviewed together.

It's unclear which members will actually make the final cut of the docuseries, but we're told the project has been completed for months ... dating back to around the beginning of the year.

As we previously reported ... the four-part series will tackle some of Justin's biggest career controversies, including Janet Jackson's infamous Super Bowl wardrobe malfunction and his highly publicized relationship with Britney Spears.

And speaking of Britney ... a source with direct knowledge tells TMZ ... she was NOT asked to sit for an interview for the project.