NEW YORK – As Gwen Stefani, lead singer for the band No Doubt, gets ready to go on stage, she looks like a pumped-up, punked-out Jean Harlow.

“I’ve always been obsessed by the days of the Hollywood starlet.” said the platinum blonde, whose coiffed, peroxide locks mix with glittery stage wear, including primary-colored cropped tanks over rhinestone-studded bras, parachute pants, Doc Martens and a gem glued to the center of her forehead (a look she says she adapted from an ex-boyfriend’s East Indian mother).

Stefani credits a range of fashion influences – from East India to East L.A., from Doc Martens to workout wear – for her glam-punk look.

Post-concert, it’s a similar style – minus the shine – with an emphasis on comfort. The rigorous tour has her relaxing offstage in Adidas workout pants and sneakers, for the most part.

The schedule has also affected Stefani’s old shopping habits.

“Before, I was always going to thrift stores,” she said, in a girlish, scratchy voice a day after a raucous concert at Roseland here. “These days I hardly have time to go get toothpaste.”

The Anaheim, Calif.-based band has been on a whirlwind tour for a year in the wake of its double platinum album, “Tragic Kingdom.” Critics and fans have rallied behind the group’s blend of funk and pop.

At her shows, the high-energy 26-year-old bounces around the stage and shows off rippled abs to the moshing fans, diving and body-surfing across the crowds.

“Are there any girls here?” she screams to the audience before belting out the hit single “Just a Girl.”

The crowd erupts in a volcanic roar, as fans approve the nose-thumbing lyrics about a woman’s perceived place in the world.

Part of Stefani’s charm emanates from a childlike aura – complete with an attentive gaze and high-pitched voice – despite her tough-girl stage persona.

After shows, Stefani strolls around backstage, shaking hands with music critics and signing autographs for young fans. It’s likely she hasn’t forgotten that the band’s nine-year ascent was built on many late shows in nightclubs and gigs in parts unknown.

A spokeswoman from No Doubt’s record label, Trauma, said the band is truly a Cinderella story. Two prior albums and a West Coast following were just fractional indicators of success. With Tragic Kingdom, the band broadened its style to include more of a pop sound than before – and hit pay dirt.

Success hasn’t spoiled Stefani.

“Gwen’s anti-drug – she’s become like a spokesperson, unofficially, for young girls in this country,” said the Trauma spokeswoman. “She’s not into that whole drugs, sex, rock ‘n’ roll thing. She’s one of the most wholesome people I know.”

Stefani still relates to the girls-next-door and they relate to her.

“I was the type who thought I could never influence anyone, this loser from Anaheim,” Stefani explained. “But I have such normal experiences – the mainstream Orange County chic-girls can relate.”

Girls relate not only to her lyrics, they also emulate her sense of fashion. The mostly teenage audiences at the shows mirror the hip-hoppish pants-and-tank combo, with many Adidas logos in the mix. And Stefani just filmed a “House of Style” episode for MTV, in which she details her tough-but-sexy chic.

“In high school, I couldn’t stand to have the same thing as everyone else,” she explained. “I always made my own clothes – and had many disasters.”

She still designs for herself, but the fashion disasters are over. Stefani has teamed with Deborah Viereck, a Los Angeles designer who also does custom work for rock stars Marilyn Manson and Seven Mary Three through her company, called ‘T ain’t.

“She goes through phases,” Viereck said. “At first it was like a Chicano gang-member look, but with touches like reflective strips.

“Then she started getting really sparkly. We do things that catch the light a lot, like sequin pants.”

Pants are key, due to the aerobic nature of a No Doubt show.

“She wears a lot of punk rocker bondage pants, in red, green, blue and yellow,” Viereck said.

In the heyday of the Sex Pistols, fans could be seen in multi-zippered numbers, usually in tartan plaid. Viereck gets in all those special straps, zippers and chains, but in Stefani style.

“We’ll do a bright yellow pant with black zippers and straps or red with yellow,” Viereck said. “Contrast is one of the most important elements of her clothing. It’s almost like a cartoon-animated style.”

When Stefani’s not touring, Viereck said, the looks are more tempered, with a retro feminine flare.

“She wears all that nice feminine clothing offstage, like cute Forties-style dresses and shoes,” said the stylist.

Stefani seems pleased with the custom collaboration. Who knows? A spinoff could be in her future.

“I would love to start a line with Deborah,” she said. “I love fashion.”