Phoebe from "Friends." According to UK musician KT Tunstall, that's the label people across the pond are quick to slap on females with guitars.

While the artist has nothing against emotional lyrics, she certainly won't be playing "Smelly Cat" anytime soon.

"There's nothing wrong with writing sad songs as long as they're original," she says. "It's a good time for singer-songwriters, but there's definitely a mountain to climb."

Tunstall — who's puzzled by constant comparisons to artists vastly different from her performance style, ranging from Bjork to Dido — has asserted her unique presence in a U.S. music industry that stresses youth and style. And she has gained immense acceptance, despite some initial culture shock.

"Oh my God, this is mental," the 31-year-old first says of the brash tone of American society and its difference from the UK, but notes she has grown to love the vibrant culture and overall crowd response, despite her age.

"My experience has been so overwhelmingly positive. People are so relieved that an adult is getting air time," she says, "Though I feel like a 7-year-old."

Over the past few months, U.S. sales of Tunstall's gold (triple-platinum in the UK) debut album Eye to the Telescope have surged as her songs were featured on comedy-drama "Grey's Anatomy," "Will and Grace" and America's answer to the UK's "Pop Idol," that pesky hour of Seacrest, "American Idol."

While Tunstall says she's made it no secret that she's not a fan of the controlled environment TV pop shows provide (for her music "is about chaos, it's about inspiration, it's about uncertainty"), she commends Idol runner-up Katherine McPhee's decision to sing a portion of her "Black Horse" on the Fox talent show — although she wasn't tuned in to Fox.

"I don't have a TV anymore, I got rid of it — it was melting my brain," she says

The Scottish-born singer concerns herself with more important causes. Not only is she talented — she's environmentally conscious as well.

When her month-long U.S. tour kicked off Sept. 8, Tunstall made sure she was cruising the nation in an eco-friendly auto — a bus outfitted for B20 biofuel, a renewable substance made from vegetable oils or animal fats that reduces toxic gas and particulate emissions from vehicles. The bus is just one among Tunstall's various efforts to give back to the environment.

Earlier this year, the artist partnered with Virgin Records and Origins Natural Resources in a cross-promotion of her music and skin care, bath and beauty products. In an effort to make concert-goers ranging from "kids who sneaked in" to "people's parents" more eco-savvy, Tunstall's gigs often feature free samples.

Even if fans don't fully embrace the Origins line, the singer-songwriter says she'll be happy instilling the simple curiosity of "where [the product] is coming from, is it tested on animals, is it full of chemicals?"

"I just thought it was such a cool way of introducing an environmentally-friendly brand of products," Tunstall says, "I grew up never questioning where the product came from."

Tonight, the Eye to the Telescope singer brings her show to a sold-out crowd at the Barrymore Theater — provided she makes it past the prime cuisine Madison has to offer.

In her experience with America, Tunstall has certainly learned two things — the U.S. is a giant country and has portion sizes to match. Tunstall (who had just eaten a burrito prior to the interview) notes she and her band have acquired quite the weakness for rice and beans, among other "American" delicacies but says they're slowly gaining a sense of self-control.

"One thing we finally learned is just to not eat everything on your plate," the Scottish-born singer laughs. "We all just go home completely fat."