Stefani a blonde with extra bottle

Gwen Stefani. Picture / Reuters

When Madonna accused Gwen Stefani of copying her style last week - "She ripped me off. She married a Brit, she's got blonde hair and she likes fashion" - it seemed like business as usual.

With a new album to promote, her Madgeness has a habit of slapping down her best friends/rivals.

But this time it was personal.

Because for many, Stefani is the new Madonna, and her debut solo album, Love.Angel.Music.Baby, is the album Madonna should have made.

It's been a great year for Stefani, a genuine pop original in a sea of Jems and Nora Joneses and Didos.

She was voted best international female artist at the 2005 Brit Awards and the album, which marries 1980s mutant electro-pop with hip-hop, has sold a staggering five million copies.

More remarkable still in the racially segregated world of American radio and MTV, Stefani, a white singer-songwriter, has achieved crossover to a black audience.

The high-profile collaborators on her solo album include the superproducer Pharrell Williams, rapper Eve and Outkast's Andre 3000.

The album's most polemical track, "Long Way To Go", deals with race issues and ends with a quote from Martin Luther King's "I have a dream" speech.

Last week in concert Stefani dedicated it to the late civil rights pioneer Rosa Parks.

But not only is Stefani more than just a pretty face, she's also more than just a singer.

Known for her outrageous fashion sense (who else would dare to wear a fur stole and hotpants, accessorised with crown and sceptre, on her album sleeve?) she also runs her own diffusion label, L.A.M.B. The range already has a cult following which includes Cameron Diaz and Paris Hilton.

In September, Stefani staged her debut catwalk show in New York, and Anna Wintour, the steel-tongued editor of US Vogue, declared, "We will soon see Gwen Stefani's range L.A.M.B.

competing with Donna Karan's DKNY."With her ash-blonde bleach and slash of carmine lipstick, Stefani combines old-fashioned Hollywood glamour with tomboy cool.

After a cameo as Jean Harlow in Martin Scorsese's The Aviator, it's been announced that Stefani will play Richie Berlin in Factory Girl, alongside Sienna Miller as Edie Sedgwick, doomed muse of Andy Warhol.

Stefani knows how to act the good girl while dressing the rebel.

She's never been snapped falling out of a club wasted.

And at the grand age of 36, a dinosaur in rock terms, she has a huge teen audience.

Despite her vampish appearance, her main audience is young women.

"When I think fans, I think girls, because my overall thing isn't sexy," she says.

Her sparky, self-deprecating lyrics mean that she is perceived as cool but authentic by her teen fans.

A self-confessed "dork" and "geek", she admits she has to watch her weight and makes no secret of the fact that her biological clock is ticking, as the first single from her recent solo debut, "What You Waiting For?", chronicles.

According to Sarah Ivens, editor of OK! in the US, "Gwen is constantly daring to be different, and searching for all things radical and trend-setting, while remaining almost sugary sweet.

"She's a girl's girl and hangs out in her gang in a way that teenage girls across the country do - dancing, trying new looks and laughing about life and boys.

"Her songs aren't just about love - they are about friendship and fights and standing up for yourself - useful things for teenagers to learn about."

So is Stefani the sex goddess with the Minnie Mouse voice, or the earnest family girl who claims she has only ever had two boyfriends and who lived with her parents until she was 30?

"She seems very benign and wholesome," says Garbage singer Shirley Manson, who has known Stefani since the mid-Nineties, "but underneath lurks an incredible toughness and powerful directness."

Stefani was brought up in Anaheim, California, one of four children in a close-knit Irish-Italian, Roman Catholic family.

Her parents were "like, totally rad", but also quite strict.

A shy girl who spent most of her time in a bedroom plastered with Marilyn Monroe posters, she nevertheless assumed she was destined for greatness.

"I'd always felt famous, at least in Anaheim," she says.

"But when it went worldwide, well, that was just plain weird.

"I'm a very private person, and so getting used to that kind of limelight was never going to be easy."

In fact, Stefani has been around a lot longer than you realise.

She first came to notice as the girl singer with 1980s ska-punk band No Doubt, founded by her older brother, Eric, and guitarist Tony Kanal.

"I had no idea I could even sing," she says, "but my brother has always been my leader, and so I just went with it."

The band developed a cult following, but it wasn't until 1997 when they released the No 1 single "Don't Speak", inspired by the torturous end of Stefani's seven-year relationship with Kanal, that they achieved global status.

Stefani has spoken frankly about the depression she suffered at the time.

But in 1998 she met Gavin Rossdale, frontman of British band Bush, and four years later they married at St Paul's Church in Covent Garden, where Stefani wore a Galliano couture gown and the groom was escorted down the aisle by Winston, a sheepdog decked out in a rose-covered collar and lead.

Cue a fairy-tale happy ending? Not quite.

Earlier this year a DNA test revealed that Rossdale is the biological father of Daisy, the teenage daughter of Pearl Lowe (from a brief fling 16 years ago).

Stefani was reportedly devastated.

But the marriage survived and earlier this year she quipped: "In my next life I am going to be a guy and I'm going to be a complete slut."After 18 years as a performer, she controls every aspect of her career, from videos to merchandising.

The only true female rock star left on US radio or MTV, she has eclipsed all the competition.

When Mrs Ritchie, pop's other big Italian-Catholic female, releases her new album, also inspired by the 1970s and 1980s dancefloor, later this month, it promises to be a fascinating battle of the bottle blondes.

Book a front-row seat.

- THE INDEPENDENT