A lion in lamb’s clothing By Elysa Gardner

NEW YORK — If you want to know how Gwen Stefani maintains her youthful enthusiasm, not to mention her girlish figure, try chatting with her for half an hour. But take your vitamins first.

“I’m just going to keep talking until you ask another question,” Stefani chirps, plopping onto a sofa in MTV’s green room. No Doubt’s 35-year-old, cellulite-free lead singer has described herself as having been a chubby teenager, but her breathless energy suggests the metabolism of a hummingbird.

“I actually have thought of myself as, like, lazy,” Stefani says. “Like, I love sleeping and eating and watching TV. But once I find something that I’m passionate about, I get this crazy drive. Because you hear the clock ticking, and you’re like, ‘Omigod, I want to do all these things, and I have to hurry up because I’m going to die soon.’ ”

Certainly, Stefani’s schedule in recent years would challenge the most determined multitasker. Since No Doubt’s last studio album, Rock Steady, was released in late 2001, she has toured extensively, gotten married — to fellow rocker Gavin Rossdale, frontman for the British group Bush — and acted opposite Leonardo DiCaprio in Martin Scorsese’s The Aviator, opening Dec. 17, in which Stefani plays ’30s starlet Jean Harlow. Late last year, she also launched her own fashion line, called L.A.M.B., an acronym for “Love Angel Music Baby.”

That’s also the title of the latest product of Stefani’s relentless drive: a new CD. Out today, it’s the singer’s first album not featuring the three other members of her multi-platinum-selling rock band.

“I can’t really call it a solo project, because it’s so collaborative,” Stefani says. No Doubt bassist and co-songwriter Tony Kanal, Stefani’s onetime boyfriend, is a contributor, as is tunesmith du jour Linda Perry (Pink, Christina Aguilera), who teamed up with Stefani for the single What You Waiting For?

Other co-writers, producers and musicians appearing on Love constitute a contemporary pop/hip-hop wish list, sprinkled with names harking back to the new wave and R&B that shaped Stefani’s youth: Jimmy Jam and Terry Lewis, Dallas Austin, Dr. Dre, Nellee Hooper, The Neptunes, Outkast’s Andre 3000, New Order’s Bernard Sumner and Prince cohorts Wendy and Lisa.

“It’s a nice name-dropping situation,” Stefani says. “I wanted to make a record inspired by the feeling of all that fun, melodic dance music from the ’80s, but to work with people who are in the club today.”

A daunting task

Craig Marks, editor of music magazine Blender, says Stefani’s approach is both bold and canny. “She seems to be an astute and voracious consumer of pop culture, and that’s what she wants to give back. It’s a pretty weird, progressive, avant-pop record, so she’s in no danger of forsaking her credibility.”

Sean Ross of Edison Media Research speculates that while Waiting hasn’t taken top-40 radio by storm, it could be that listeners “haven’t caught up with it yet. But they certainly want her to have a hit.”

But Marks acknowledges that a solo debut, whether the artist wants to call it that or not, “always poses a bit of a risk. Gwen really seems to have enjoyed being with the boys in her band, and that security blanket isn’t there now.”

Stefani concedes that recording Love was more daunting than she had anticipated. “After 17 years of being in this little comfort zone with my best friends, I had to walk into a room with these people I hardly knew and totally admired. It was like, ‘OK, I’ll take my clothes off. I know you totally have expectations of me, but let’s get intimate.’ It was horrifying, but once you get over that hump and the song comes out, you have this little thing that you made together, and it’s there forever.”

That Stefani would describe her creative process in such terms seems fitting for a self-confessed “girly-girl” who thrives in male company. “I love that contradiction of being feminine but playing in the boys’ treehouse. My whole life’s been like that.”

Her fellow players on Love encouraged Stefani to explore her own womanhood and, on tunes such as Bubble Pop Electric and the Asian-influenced Harajuku Girls, try on different voices. “Usually, I write about whatever I’m inspired by that day,” she says. “But I also got to play characters here and there, which added a nice balance.”

Stefani, who is considered one of pop’s coolest clotheshorses, adds that starting up L.A.M.B. further fired her juices. “I was designing and starting to write the record at the same time, so there was a lot of cross-pollination going on.” She adds, “I think I can confidently say that designing is something I want to do for the rest of my life. It’s such a passion for me, and there’s no emotional stress involved, whereas music is very emotional.”

More films may also be part of Stefani’s future, though she stresses that she has only a couple of lines in Aviator, in a scene where her Harlow appears with DiCaprio’s Howard Hughes. “I definitely got my feet wet, and I got to do it in the big pool. And everyone was so amazing and welcoming, from Leonardo to John C. Reilly to Jude Law. … There I go, name-dropping again.”

For all her celebrated chic, in fact, Stefani still seems less than comfortable with certain aspects of celebrity. “At a certain point with fame, you have to learn boundaries. Or else it’s like, ‘OK, I think an insane asylum looks really comfortable right now.’ ”

On the home front

Stefani’s own boundaries, predictably, do not extend to discussing recent tabloid reports that Rossdale has a teenage child from a previous relationship. Asked if she and Rossdale plan to have a baby of their own, Stefani says, “I want to have children, but I feel weird talking to the whole world about that, because it’s my business. And it’s not really up to me, you know? If you see a bump on my belly, then you’ll know I’m having a baby.”

Stefani concedes that there have been significant changes in her personal life since No Doubt rose to fame in the late ’90s, and in the lives of Kanal and bandmates Tom Dumont and Adrian Young. “Tom just got married, Tony’s in a really serious relationship and Adrian has a 2-year-old with his wife. And I’m married, obviously. Everybody grew up. And when you marry, that becomes your priority.”

In spite of that, and her own ambitions, Stefani insists that “the band is totally still together. Tony was very involved in my record, and we put a greatest-hits record out. When you are in a relationship that many years, you have to recharge the batteries. Now we can start flirting about making songs together again.”

Granted, Stefani’s pop life may not remain as chaotic as it has been lately. While she’s doing a promotional tour for Love, there are no plans for the kind of concert trek that No Doubt’s fans have looked forward to after each CD.

“I’ve done so much touring in my life,” Stefani says. “I love it, love it, love it. On the greatest-hits tour (No Doubt) just did, it was incredible to watch those crowds. I cried at every show. But life just feels so short right now. Maybe that’s what happens when you turn my age.”

Not that Stefani is complaining. “I feel pretty filled up with everything. I feel like maybe I can take a breath and go, ‘OK, I’ve done all these things; now I can just enjoy the moment.’ For the first time in a long while, I can’t even see tomorrow. But I know that something is going to surprise me.”