Image copyright Jordan Corrin Image caption "There's nothing like walking out to 60,000 people at Wembley," says Anastasia Walker

Anastasia Walker was sitting in her pyjamas, eating Coco Pops and watching Jeremy Kyle, when she got a phone call that changed her life.

"Pink's really interested in bringing you out on tour," her manager said. Not just for one date or two, but every night of her European stadium tour.

"It's totally mind-blowing," says the singer, who's fronted the in-your-face pop trio Bang Bang Romeo since 2010.

"You work your whole career to get to this point, to play these stages - and now we've done it."

When the BBC catches up with Anastasia [Stars to her friends] she's back in that same living room, wearing the same pyjamas, enjoying a three-day break from Europe's enormodromes.

"It feels weird not to be on a tour bus," she laughs. "I'm walking around the house, wobbling and holding the walls because I'm so used to the motion of the road!"

Beer mat beginnings

It's not difficult to see why Pink chose Bang Bang Romeo as her opening act. Their defiant spirit and messages of tolerance chime perfectly with the star's own nonconformist brand - while Anastasia is one of those rare performers whose powerhouse vocals are a perfect match for her exuberant stage presence.

She's been performing since the age of seven, when she grabbed the mic at her local pub's karaoke night.

"I sang Dancing Queen, and someone picked me up and put me on a table so people could see me," she recalls.

"I'd never sung in front of anyone before, but the place erupted. I was signing beer mats afterwards!"

"After that, it was like, 'Alright I can sing, I need to learn guitar'. And I did my first ever gig on my own when I was 14 in the Vintage Rockbar in Doncaster."

Image copyright Matt Spracklen Image caption The band consist of (L-R): Richard Gartland, Anastasia "Stars" Walker and Ross Cameron

But at the same time as she was building a name on the local music scene, Anastasia was struggling to come to terms with her sexuality.

"I was a young teenage girl in what was essentially a mining village," she says. "I'd never met a gay person in my life and no-one at my school was openly gay.

"So coming to terms with my sexuality was really tough. I was that scared of coming out, or accepting it, that I turned to self-harm."

It was the support and understanding of her family that helped her face down her fears.

"I was very lucky when I came out to my dad and my grandparents, because the general vibe was, 'Yeah, so? What do you want for tea?'

"It was so blase, it was brilliant. What a beautiful thing, that I was able to be brought up like that by my family.

"And I think I asked for fish fingers."

'Walking backwards'

Anastasia says the lack of a visible gay role model in her teenage years has made her determined to fill that role for fans of Bang Bang Romeo.

"I get a lot of messages from teenage girls and boys, who are coming to terms with their sexuality," she says, "and if I can make the tiniest bit of difference, I'll help.

"Because I don't want that young girl who's scared to come out to turn to self-harm, and to turn to a very dark place mentally, because when it gets dark, it can turn pitch black, and we don't want that."

The message is scorched into their music, too.

The video for Bag Of Bones depicts a woman going through the process of becoming a trans man; while a recent cover of 90s anthem What's Up features drag queens Morgan McMichaels and BibleGirl.

"I want to spread the word that we're all exactly the same," says the singer, "because right now, it seems like we're walking backwards."

She was "really rattled" by the homophobic attack on two women on a London night bus earlier this year.

"They got punched in the face. They got beaten for being gay," she says, still astonished.

"I shouldn't have to worry about where I go in this world. It shouldn't matter, and I feel like it's becoming a thing again.

"I mean in Birmingham, two hours down the road from me, there were parents protesting outside a school to stop gay education. God, it was so upsetting. Imagine being a gay child in that school."

That's why the singer is proud to be supporting Pink - who's been preaching about acceptance on every stop of her world tour.

"I don't want there to be gay marriage," the US star says, echoing comments she first made in 2010, "I want there to be happy marriage and lasting marriage and healthy marriage."

"I'm all for that," says Anastasia. "The role models aren't there, in terms of leaders of our countries, so we need people that are trying to set a standard of how we should feel and be."

However, the tour has had one downside: Forcing Bang Bang Romeo to delay their debut album, A Heartbreaker's Guide To The Galaxy, until September.

They've also deleted the video for fan favourite Chemicals from YouTube, suggesting the song is being primed for re-release.

"We do have plans for Chemical," Anastasia says coyly, "especially because, on the Pink tour, that song has gone down incredibly.

"If you look online, you'll see 60,000 people singing along - which is mental, really, because 99.9% of them have never heard of us before."

The reaction is "heartwarming", because Chemicals was the band's first song, written by guitarist Ross Cameron back when they were still teenagers.

Gaming Facebook

Along with drummer Richard Gartland, they've been playing in earnest for five years, harnessing a new data-crunching platform called Beatchain to help them identify clusters of fans and promote shows in those areas.

The site works by "scraping the internet" to identify which posts are connecting with fans, then contextualising them against "other, similar-sized bands in their genre," co-founder Luke Mendoza tells the BBC.

"Traditionally in the music industry, promoters don't talk to managers, and they don't talk to the labels, so everyone has little pieces of data, but nobody has the whole picture," he says. "But once you see that big picture, you get some insights from it."

For Anastasia, the attraction is more simple: "Facebook and other apps try and shaft you because unless you keep paying, not everyone's going to see your posts.

"Beatchain targets the people who have liked our page [so] fans can actually see what we're saying. It makes a massive difference, and it's two fingers up to Facebook."

Image copyright Jordan Corrin Image caption The band, whose song Cemetery is an ode to Record Store Day, have poured extra effort into the vinyl edition of their album

But after playing to more than a million people this summer, social media manipulation should become increasingly unnecessary.

Bang Bang Romeo's own tour this autumn has almost sold out, and several venues have had to be upgraded; while Anastasia hints the album's artwork - in which every song is represented by a planet - will be brought to life on stage.

"We're so excited," she says. "It's going to be a ride, this album."

She'd better get used to wobbling around those tour buses. There'll be a lot of them in her future.

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