When I first meet Kelis Rogers, shock-headed, motor-mouthed pop diva, she's foaming at the mouth. As she opens the door of her hotel room in Covent Garden, west London, a rather large blob of toothpaste dribbles down her chin.
"Hi, I'm Kelis," she says brightly, beckoning me in with her toothbrush. The room is strewn with clothes, bottles and magazines. A large trunk, spilling over with shoes, scarves and some fabulous multicoloured coats, sits on the floor. MTV blasts from the television. It looks as if she's been here some time.
The singer eventually emerges from the bathroom, smothered in face-cream.
"Sorry about the mess," she yells over the music. "It's a wreck, but I haven't been home for months."
Kelis shouts a lot, although that's not entirely surprising. Her debut single, "Caught Out There", a cautionary tale about infidelity, is best known for its thunderous chorus: "I HATE YOU SO MUCH RIGHT NOW. AAAAAAAARGH!" The song wasn't personal, she says. It arose from listening to the experiences of other people, in particular her sisters. Is she sick of it yet? "For a while I hated it, but now I just think it's my song. When we were recording it, I knew it was pretty intense but I thought, 'Well, they'll love it or they'll hate it but at least they won't miss it.'"
It's always been difficult to know where to place Kelis. She has the voice of a classic soul diva, though musically she casts her net a lot wider. On her forthcoming album Wanderland, you can hear traces of R&B ("Scared Money, "Flash Back"), soul ("Shooting Stars"), hip hop ("Daddy"), rock ("Young, Fresh n' New", "Perfect Day") and even a touch of Eighties synth ("Easy Come, Easy Go"). On tour, Kelis travels with a huge live band and has become notorious for her raucous covers of Nirvana's "Smells Like Teen Spirit" and The Eurythmics' "Sweet Dreams". The singer's eclectic impulses are matched by those of her producers, Chad Hugo and Pharrell Williams, aka The Neptunes, who recently released their own album under the moniker NERD.
"People have very different perceptions of who I am and who I speak to," she says. "I can only do what I do. When people try to pigeon-hole me, I think, 'Surely that's not the point.'"
Kelis the person is even harder to pin down. First impressions bring to mind a young Tina Turner. She has the wild hair, the big laugh and the tough-nut exterior. She's no pampered princess, either. She chooses her own clothes ("I buy this stuff to wear. I wear this out"), does her own make-up and looks after herself like any normal 22-year-old.
She's tremendously energetic. Even in the middle of promoting an album, she's thinking about film scripts, ideas for television, possibly even starring in a musical. When she's at home in New York, she says, she goes to see musicals all the time, sometimes two in a day. Is there any end to her ambitions, I ask.
"Absolutely not!" she cries. "Music is what I get a buzz from right now, but that could change. This is not the end for me; I'll do tons of other things. I want to have stories to tell when I'm old."
Kelis says she's happy with her progress so far, but not at all surprised. She is of the mind that what you work hard for, you generally get. But being a female artist in a male-dominated industry surely comes with its problems.
"Women are more emotional, more naturally passionate about things," she reflects. "But men don't deal with emotional outbursts well. In the workplace you have to succumb to what it is that makes them understand you. That's a successful woman – someone that can make herself businesslike, but in a non-threatening, female kind of way.
"Sure, there's always going to be differences of opinion that arise from gender. Unfortunately, there's no middle gender to decide who's right or wrong. It's going to be an ongoing battle until the end of time."
In fact, the majority of Kelis's close friends are men – she calls them her "harem". She admits that she's more comfortable around men, although she's not above criticising them.
"Listen: women clearly have the upper hand, and we know how to use it. We can work with men. They're very simple. I mean, how many times have you asked a guy that you're with, 'What are you thinking?', and he says, 'Nothing'? It took me a long time to actually believe that. But really, they think nothing a lot of the time."
When I ask if there's any sense of solidarity among her female contemporaries in the music industry, she shrugs.
"To be honest, I don't really know any of these people. But I think it's like high school – if you're not part of an in-crowd, you're seen as an outsider."
Kelis grew up in Harlem, New York, alongside three older sisters. All of them sang in her local gospel choir, the Girls' Choir of Harlem. Advice offered by her mother proved crucial in Kelis's development. Iveliss, a children's clothes designer who custom-made outlandish outfits for her daughters to wear to school, arranged for her youngest child to learn violin from the age of two and the saxophone from her early teens.
"She wasn't one of those pushy mothers," she reflects. "What she told me and my sisters was that, to be happy in life, you have to nurture the things you're naturally good at. I knew music was what I was good at."
From the age of four, Kelis was also performing in nightclubs across America with her father, the jazz saxophonist Kenneth G Rogers, who later became a Pentecostal minister. Though Kelis knew that she wanted a career in music, she decided to keep her options open. At 14, she enrolled at the LaGuardia High School for Performing Arts, the institution immortalised in the film Fame and its television offshoot, in order to study theatre. Students spent half of each day studying the usual academic subjects and the other half concentrating on their "craft".
"They never showed the academic side on that show, but there were kids dancing in the halls when I was there. In the afternoon we had to go downstairs – we were called the basement babies. We had to take off our normal clothes and put on black for the rest of the day and walk around in character. At 14 years old, that's really intense. I hated it when I was there, but now I look back and think, 'That was the shit.'"
Aside from the odd bit of musical theatre, Kelis never did any singing at school. She knew she could do it well, she says, so why bother with being trained? Instead, she started a girl group with her friends from school, known as BLU (Black Ladies United). It was with this band that she caught the attention of the hip-hop producer Goldfinghaz, who arranged a guest slot for her on the second album by the RZA's side-project, Gravediggaz. Over the next two years, Kelis developed some impressive contacts, befriending The Neptunes and making guest appearances on Ol' Dirty Bastard's ode to pimping, "Got Your Money" and Puff Daddy's "PE 2000".
Not surprisingly, Kelis was quickly snapped up by a record company and within six months had recorded her first album. Kaleidoscope confirmed her as one of the most interesting personalities in the R&B/hip hop firmament and notched up three Top 40 hits and a Brit award for best newcomer. Now, she seems set to consolidate that position with Wanderland. It's packed with attitude and is perhaps even more ambitious in scope than her debut.
When I ask Kelis if she thinks it's better than the last one, she cries: "Absolutely. You get older, you get better. That's the rule, right? I'm a little bit calmer, a little older; I don't feel as frantic. I have clearer thoughts now, and I think that manifests itself in the music. I think it's a great album."
The single 'Young, Fresh n' New' is out now on Virgin records. 'Wanderland' is released on 29 October