Adam Lambert finally feels like he has been granted ''permission'' to be himself on stage.

The 'American Idol' alumni was out as a gay man in Los Angeles long before he shot to fame on the talent show in 2009, however he only experienced homophobia once he became famous.

The 'For Your Entertainment' hitmaker admits it was a huge ''wake-up call'', especially as there is no guidance for LGBTQ celebrities.

Speaking to The Guardian newspaper, he said: ''No one gives you an instruction guide on how to be a queer celebrity.

''Ten years ago, it wasn't a lane that was really that clear.

''I'd been in the arts, in Los Angeles, my whole adult life at that point, so [my sexuality] wasn't an issue.

''Then all of a sudden, I was like: 'Oh sh*t, this is what homophobia is.' It was a wake-up call for me. It was sad.''

The 36-year-old star - who balances his own career with fronting Queen in the place of late great frontman Freddie Mercury - says a decade on, he finally feels his music isn't judged based on his sexuality.

He admitted: ''I needed an outlet for me that wasn't judging.

''I needed to be in a safe space that didn't say to me: 'Don't do that, people won't like that.'

''Now there's an audience for me being exactly who I am. There's permission given.''

Earlier this month, Lambert hosted a Q&A at LGBTQ youth centre Mosaic in London, where he spoke about the challenges he faced as a gay man entering the pop business and how he felt like he had to ''prove'' himself.

There he admitted he has learned to find a ''balance'' between putting out art that is ''commercially palatable'' and staying true to himself.

The star was asked about the backlash he received early on in his career, to which he replied: ''There have been moments early on, where I felt I needed to prove something, and make a point that wasn't necessarily a popular one. By principle, I believed in it - but then you have to balance it out, it's a business and I have to be palatable and commercial. I guess I had a struggle in finding the balance - but I don't have any regrets.''