It's four years since Adam Lambert last released an album - but it wasn't touring with Queen that put the brakes on his solo career.
"I was fried and disillusioned," says the pop star.
He was "second-guessing" his music and feeling "detached in my personal life," so he hunkered down and asked himself the tough questions: "Am I doing this for money? Am I doing this for attention? Am I doing this because I love music?
A few things became clear: Making and playing music were still his passions, but the business side of the industry was "making me sad".
"I was making my happiness dependent on my commercial success," he explains. "It was unhealthy. I had to rethink things."
The result is his new EP, Velvet: Side A - a liberated, funky take on '70s rock that provides the missing link between Queen and the electro-pop of his solo albums.
Critics have all called it his "best work yet," and it will be followed next year by Velvet: Side B, featuring the previously-released songs Feel Something and New Eyes.
Dressed in a long, sheer poncho and festooned with jewellery (including a gigantic silver ring in the shape of a sphinx), Lambert sat down with the BBC for a wide-ranging chat about sexuality, new music, the future of Queen, and why he's an advocate of electoral reform.
Here are the highlights.
Coming out is 'an act of defiance'
Lambert had already come out to his family and friends when he took part in the eighth season of American Idol in 2009, but when pictures of him kissing his ex-boyfriend emerged during the show's run, it made headlines in America.
Fox News ran a segment on the singer, calling the photos "embarrassing", while Entertainment Weekly put Lambert on their cover with the disingenuous strap line: "The Most Exciting American Idol Contestant in Years (And Not Just Because He Might Be Gay)."
"It was stressful and it was confusing," says the star. "I was like, 'What am I supposed to do?'"
"In hindsight I realise there is power in coming out. The act of declaring your sexuality publicly, once you're a public figure, is an act of defiance in some ways, and it's also a form of activism."
And he's pleased that queer artists are becoming more and more visible, with the likes of Christine + The Queens, Olly Alexander and, especially, Sam Smith showing that sexuality is no longer the barrier to success it used to be.
"Sam is a really interesting example because they have been able to be fully mainstream," he says. "I mean, mums and dads are buying Sam's album. That's a big move, a big step."
Taylor Swift's LGBT activism is "admirable"
Lambert has a cameo in Taylor Swift's colourful video for You Need To Calm Down, dressed in biker gear and giving Ellen DeGeneres a tattoo in the back of a caravan (as you do).
Swift intended the video, which was packed with queer and trans celebrities, as a message of solidarity with her LGBT fans - but was later criticised for "commodifying queerness" to sell records.
"I can see both sides of the controversy," says Lambert. "People are like, 'Oh, she was exploiting the community for her own gain'. But the thing that excuses that is that she called people to action. She got a ton of signatures on a petition for the Equality Act," which would ban discrimination based on sexual orientation and identity.
"That's real action, so it's not just for personal gain. She's putting her money where her mouth is, and I thought that was really admirable."
He won't record new music with Queen
"The Queen train is full speed ahead," laughs the star. "I think the movie [Bohemian Rhapsody] has taken things way over the edge.
"I mean, we were doing fine before, don't get me wrong, but now it's stratospheric. And we're seeing much younger people in the audience. There were always some young people but now it's all ages. New fans."
The band have just announced tour dates for 2020 - marking Lambert's ninth year as frontman. But he says they've never been tempted to make a new Queen album.
"It doesn't make sense to me," he says. "It just doesn't click.
"I don't know how else to describe it, but there's never been a real reason to do it."
Adam's gone indie
Not that Lambert has suddenly become The Smiths or anything; but his EP was inspired by artists like Billie Eilish and Lana Del Rey, who ride in the outer lanes of the pop mainstream.
"I'd been listening to the Top 40 and going, 'I don't like a lot of this music,' and I was gravitating towards indie stuff that wasn't cookie-cutter pop.
"It was more adventurous and moody, and I wanted to do something in that vein: Slightly more indie and slightly less trend-based."
Keeping it truly independent, Lambert left his former home at Warner Bros to release Velvet on the smaller, indie label Empire.
"At a major label, it's always a compromise," he says. "There are certain ulterior motives, and most of them are money-related. I wanted to be in a situation where I could be in the driver's seat and say, 'This is what I want to put out.'"
Feel Something was written at his lowest ebb
"I don't need to feel love / I just wanna feel something," sings Lambert on Feel Something, a vulnerable and emotional ballad that became the first single from Velvet. It was quite a departure for the singer, but he says it was crucial.
"I didn't want to put out my big crazy pop single first," he says. "I wanted to tell a story about what I've gone through and Feel Something was a way to sum that all up: This is where I was when I was hitting the bottom, and kind of bummed out."
His vocal performance on the song is uncharacteristically raw - something he wouldn't have attempted at the start of his career.
"Ten years ago, I would attack things with a lot more energy, theatrics, attitude," he says. "So it's little bit of a change to pull it all back."
New Eyes is all about falling in love
Lambert met his new boyfriend, Javi Costa Polo, on Instagram and he helped Lambert rediscover "all the things I was longing for in Feel Something".
The song New Eyes is all about him, says the star.
"The new pair of eyes that came into my life are very hopeful and very positive," he smiles.
"There's an innocence there that I'm really drawn to. The freshness, the hunger for new experiences: I love that."
He made Cher cry
Lambert reduced Cher to tears last December when he performed a stunning, stripped-back cover of her biggest hit, Believe, at the Kennedy Center Honours.
It was a "wild" night, he says, but it almost never happened.
"They were expecting me to perform Believe the same way as the record - but I was like, 'No, the Kennedy Center is highbrow and sophisticated, why don't we do it like a ballad?'
"At first they weren't sure, but I said, 'Would you please trust me?' and I'm really glad I pushed for it - because I think that's what made it such a moment."
Queen won't be touring with Abba
When Lambert performed for Cher, she was in the middle of promoting Dancing Queen, her album of Abba covers. But when we suggest an Abba / Queen double bill, the singer is sceptical.
"Queen and Abba? Do they belong on the same bill? Do they?" he asks incredulously.
Here's a counter-argument: Queen and Abba sharing Glastonbury's legend slot would be amazing.
"I guess you're right," he concedes. "Going on tour together wouldn't be a good fit. But at a festival? That'd be a great night."
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He's an advocate of electoral reform
"I'm not a protest songwriter in any way," says the star, but his latest single, Superpower, "does tap into the zeitgeist of people feeling frustrated" and downtrodden.
Lambert wrote the slick, funky pop track three years ago "but it still feels topical," he says, because "the political situation in America is terrible".
However, he believes Donald Trump's presidency is a "tipping point" that's energised a "progressive" youth movement.
"People go, 'Is he going to get re-elected?' and I just feel like the chances of that are so slim, because he barely got through the first time - and that's before we realised just how bad he was going to be."
"But there's problems," he adds. "It's a corrupt system. The fact that they make it so hard for people of colour, and so many other minority groups, to vote. It's screwed up."
The solution, he suggests, is to overhaul America's electoral system.
"At the time the [electoral college] system was created, it needed to be that way, but we're in a different era now. It's dated.
"I don't see why they just can't make it a square vote, where everyone in the country votes and the person with the most gets in."