Ke$ha: 'You don't tell Alice Cooper what to do'

May-to-December, cross-genre collaborations maybe aren't the surprise they once were. When, in 1977, David Bowie dropped in to Bing Crosby's Christmas TV special to record a version of Little Drummer Boy, it was enough of a shock that the song appeared on bootlegs for several years before being officially released as a single in 1982. Now, though, thanks to the raft of duets albums bringing us pairings such as Frank Sinatra and Bono, and Tony Bennett and Lady Gaga, there is perhaps less of a frisson.

Nevertheless, there are still some combinations that can raise an eyebrow. If, for example, Alice Cooper were to record a follow-up to his 1975 album Welcome to My Nightmare, and was seeking someone to play the role of the devil, you might expect him to summon one his shock-rock heirs – Rob Zombie, perhaps, or someone from Slipknot. You might not expect his collaborator to be trash-pop princess Ke$ha. However, that's her on What Baby Wants, Baby Gets, on Cooper's new album, Welcome 2 My Nightmare. That Iggy Pop/Miley Cyrus team-up is only a matter of time.

"I'd love that," says Cooper when I moot the idea of the Stooge duetting with Hannah Montana at the start of my conversation with him and Ke$ha.

"Who fucking knows, man?" Ke$ha says, sounding less bratlike and more businesslike than you might imagine. "You really can't stereotype people or put them in boxes, it's unfair. You never know what an artist is going to create next."

There's actually quite a lot of common ground here. There is the idea of them both as stage creations – Cooper was once the clergyman's son Vincent Furnier, while Ke$ha used to be Nashville country girl Kesha Rose Sebert. There is the way they both talk about themselves in the third person. There is a shared propensity for the gory (he does on-stage garroting, she's into dismemberment – she drank blood from a heart on her Get $leazy tour) and mildly transgressive (his shock tactics, her song C U Next Tuesday and tendency to have dancing transsexuals on-stage). They even have links to The Simpsons: Cooper supplied a storyline for a spin-off comic book, while Ke$ha's multi-million selling single Tik Tok was used as a replacement intro theme for the TV cartoon, the only time in its history that has happened.

It's almost a wonder it took them so long to join forces.

"A lot of people in the business look at the two types of music we make and wonder how they can go together," Cooper says. "But I'm like you, Ke$ha, when people tell me no, I immediately want to do it."

So how did you two meet?

Ke$ha: I hunted him down at the Grammys. And then a year later I'm on Welcome 2 My Nightmare! This is my fantasy. Working with a legend makes me excited to bring that rock'n'roll energy to whatever evil dark metal album I decide to make in the future.

Cooper: The thing I liked about her is she looked like a rock singer. I think she's going to wind up with a band behind her as a sort of female Robert Plant. You've got that stature and attitude. And that's why I wanted you to play the devil on my album.

Ke$ha: I'm not a submissive, perfect pop princess, that's for damned sure. I do think I have a rebellious, metal-loving rock chick inside of me. This song is the world's first look at the evolution of that. I've always loved rock'n'roll. It's about subversion. I'm talking to millions of people around the world about having sex freely, getting hammered, and partying. It's fun for me to be riding that line of appropriateness.

Are you playing with what's acceptable?

Ke$ha: I'm here to level the playing field. Chicks can talk about the same shit that guys can, and they can be just as badass.

If Ke$ha had been around in 1969, would she have held her own with Janis Joplin?

Cooper: Yeah, I think so. But it would have been different. Janis didn't work on image very much. She was this big voice from Texas. Whereas Ke$ha really works on the image.

Ke$ha, are you satirising teen America, their voraciousness and bloodlust when it comes to consumption and sex?

Ke$ha: Absolutely! And you either get it or you don't.

You've written a song for Britney. What do you think she and the other young women of mainstream pop make of you?

Ke$ha: I'm not really concerned with what people think of me and that's what I've really built my career upon, so I have no idea.

Cooper: I think, knowing those girls, Ke$ha would get along with Gaga. Because they're both more outrageous than the others. Katy Perry is outrageous in a Sleeping Beauty kind of way. Ke$ha and Gaga are more arch.

Ke$ha, when you first came along, did people miss the sense of play about what you do?

Ke$ha: They missed the tongue-in-cheek aspect. What I'm doing is art – it's low-brow art but there's a magic in that.

So you're not trashy, you're satirising that?

Ke$ha: It's a little bit of a satire.

You're both into ghoulish stuff. Is it to wind people up?

Ke$ha: No. A song like Cannibal where I like to dismember one of my dancers and pour his blood in my mouth and spit it at people – that came about because I really do devour men at a very rapid speed, and usually – by the time I'm done with them, I've literally sucked the blood out of their hearts.

Cooper: When Ke$ha and I sat down to write the lyrics to our song, the more disturbing ones were hers. The ones about, "I'll bathe in your blood" and "I'm gonna chew through you" – all Ke$ha.

Is it weird, Ke$ha, to have gone so quickly from thinking about fame and success to actually living it?

Ke$ha: I've always lived as though I'm a fucking god. It never had to do with money, though. I grew up with no money, but I never went without anything, it just made me creative and crafty. I used to just steal shit, or sneak into places. I would drive around LA in a Mercedes that some dude gave me. When you have the mentality that you're going to live a lavish lifestyle, [not having] money can't stop you.

Alice, you're a born-again Christian. How does that tally with Ke$ha's naughty antics?

Cooper: Everybody has to survive. When we were a young band starving in LA we had to steal. A guy would invite his girlfriend over and they'd go in the bedroom and we'd go through her purse and get 20 dollars. That would literally feed the band for a week.

You've both made cameos at each other's shows. Whose audience is scariest?

Cooper: There's metal audiences that are pretty dangerous, that if you fell in it would be like falling into a pit of piranhas. But they like Ke$ha because she doesn't come off like a pop diva. She comes off like a tough street kid.

Ke$ha: And I have big tits and blond hair – why wouldn't they like me?

Do you find yourself wanting to top the last outrageous thing you did?

Ke$ha: It's not really "topping" the last outrageous thing for me. I just come up with more crazy ideas to show the world I'm not scared of looking like a freak.

Ke$ha, you've had a tattoo from a crack addict and cavorted with transvestites, and Alice, your history of outrage precedes you. Is it more difficult to shock these days?

Cooper: You can't shock an audience any more. When you turn on CNN and you see a guy getting his head cut off, the reality is so much more shocking than anything any of us can do onstage.

What was the last shocking thing you heard?

Cooper: I was shocked to hear that Ke$ha was on my album.

Ke$ha, did you hold the whip hand in the studio?

Ke$ha: No. But I do like that I grossed Alice  Cooper out with my lyrical content. It's an impressive moment in my songwriting career.

What did your friends think when they heard you were working with him?

Ke$ha: I'm friends with a few gutter-punks in LA who were literally blown away. Because he's like a god in the circles I run in.

Have you, Alice, ever felt compelled to give her fatherly – or grandfatherly – advice or told her to take care?

Cooper: I think the one thing that Ke$ha and I have in common is that we're not careful about anything.

Ke$ha, have you ever felt like telling your surrogate dad to get lost?

Ke$ha: Fuck, no! You don't tell Alice Cooper to do anything.

Welcome 2 My Nightmare is released on 17 October on Spinefarm