Out singer Adam Lambert said in an interview this week that his biggest challenge following American Idol was learning how to be an openly gay celebrity.

Lambert appeared on BUILD to promote Queen's upcoming residency in Las Vegas. Queen with Lambert as frontman will play a 10-date engagement at the Park MGM in the fall.

“We're ready to take on the ultimate challenge – to dazzle Las Vegas,” Queen guitarist Brian May said in a statement.

During the Q&A session of the interview, Lambert was asked to name the most challenging part of his journey post American Idol.

“One of the things that was, you know, obviously, like, a big talked about thing was being openly gay,” Lambert answered.

“There's a lot of learning curve that comes with becoming famous. All of the sudden you realize, “Oh, I have to watch what I say.' And I have responsibilities now to other people, to fans and to the LGBTQ community.”

“It was very interesting to grow into that and to learn about it. I was up for the responsibility, but it was revealed to me very slowly what that responsibility was. You know, no one gives you a handbook, like, 'Surprise, you're a gay celebrity, you know, do your thing,'” Lambert said.

(Related: Adam Lambert “loving” Troye Sivan's “Bloom”; Performs duet with Melissa Etheridge.)