When eventual runner-up Adam Lambert hit American Idol back in 2009, the buzz about the singer wasn’t only focused on his stellar vocals–much of the din about Lambert instead was about his sexuality, which he didn’t address directly until after the season was completed.

It’s still a hot topic, as Lambert discusses when he first realized he was gay in the latest episode of VH1’s Behind the Music: Adam Lambert, which will air on the cable network Sunday, August 7, at 10 p.m. EW has the exclusive preview clip of the hour-long episode.

“When Adam was younger, he had an imagination that was wild,” his mother, Leila Lambert ,says. “He loved to put on costumes and make-up, and he loved to play all kinds of characters.” Lambert himself chimes in: “My parents put me in a theater program and that was to kind of channel some of my excess energy. They put me in indoor soccer and t-ball and, surprisingly, neither one of those really worked out for me,” he says with a laugh.

As he got older, though, the identity crisis began. “I think when I was about sixth grade, that’s when I realized that I was probably not the same as the other boys,” Lambert remembers in the clip. “And, you know, it was a weird discovery and, of course, I was kind of in denial for a while and it was all in my head. To me, it was a deep secret. I was just not ready to talk about it with anybody. I didn’t know how my parents would react, and I didn’t know what that would be like, and I think, at at that age, it was something that I was ashamed of because it was so different and wasn’t the norm and not encouraged and no one talks about that in school. That’s one of the things that’s so hard about being a young person and realizing you’re gay or bi or whatever–we’re not told that that’s okay.”

Of course, Lamert’s sexuality isn’t the only thing chronicled in the Behind the Music episode — the hour gets into his rise through theater, his time on American Idol, and his controversial American Music Awards performance in the fall of 2009. Friends, family, and music industry folks–including Barry Weiss and American Idol season 8 winner Kris Allen–also chime in on the special.

EW has the exclusive first look at the episode here:

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