Lea Michele Once Showed Jonathon Groff Her 'Whole Vagina' -- for Educational Purposes

15 years later, HBO is celebrating the iconic show's anniversary with a new documentary, "Spring Awakening: Those You've Known." In the original production, Michele and Groff were discovering themselves, their bodes and their burgeoning sexuality as ill-fated 19th Century teen lovers.

That intimacy carried over into their personal lives, where Groff was still living as a closeted gay man before ultimately coming out in 2009.

"Lea and I were given this material where we had to fall in love, but the first thing I felt was, 'They're going to know I'm gay. Fuck! I never had sex with a girl. I'm in the closet,'" Groff said in the documentary.

"Jonathan and I became so close. We were so intertwined," Michele shared of the production, which included partial nudity for both of them during an intimate sex scene -- and that was just the first act!

Apparently, things got so comfortable between the two of them -- and remains that way to an extent -- as Michele candidly shared that she once "literally showed him my whole vagina."

"I can confirm that," Groff agreed, though it was more for scientific curiosity than anything else. "He was like, 'I've never seen a woman's vagina before. Would you show me?'" Michele recalled, and I was like, 'Sure.'"

"That's how close we are," she said, though Groff did not return the favor. Nevertheless, Michele is grateful for the closeness of their connection off stage, as she feels it helped them on stage, telling People it gave them a special "level of trust."

"If we didn't, I think it would've been really impossible and just so challenging to have to tackle that material every night with someone that you don't feel that safety and trust with," Michele told the outlet.

The "Glee" alum said that feeling "safe and comfortable" is why she shared the unorthodox story, telling Entertainment Weekly that the documentary's producers made them willing and able to be so open.

"With that level of comfortability came a story of just what goes on behind closed doors between me and Jonathan Groff. That’s only one of them," Michele told EW. "There’s a lot of other things."

"There’s a lot more than that story, for sure," Groff agreed, though neither offered to share.

"Honestly, the great thing about this documentary is it's a wonderful microscope into who we are as individuals, and not just who people think we might be," Michele added.

The actors agreed that the heavy subject matter of the production, which included abortion, rape and suicide, was taxing emotionally. Michele told Billboard that she recalled telling Groff one night that she wanted to "be in a show that’s the happiest show in the world."

"I want to do musical numbers with fireworks and tap-dancing with Kristin Chenoweth," she said she told him. Of course, that's exactly what would happen, as Michele's next big project was "Glee," which featured both Chenoweth and Groff in recurring roles.

"I guess put it out there and it’ll come to fruition," she laughed. "But I truly knew I needed to do something a little lighter."

"Spring Awakening: Those You've Known" celebrates the 15th anniversary of the Broadway show with interviews and a one-night-only production featuring the original cast. It premieres on HBO May 3 at 9 p.m. ET.