Sprawled on her bed in an Amsterdam hotel, Lady GaGa is channeling Lady Godiva-sans the horse.

While the 23-year-old has famously worn everything from Kermit the Frog to a hat made to resemble the solar system, today she's rocking the one constant in her ever shifting wardrobe-underpants. And nothing more.

But despite her dominance on the pop charts worldwide and bleached blonde hair, GaGa is not the average pop tart. She's an accomplished songwriter and performer who seems to have come out of nowhere, bursting from the corner of Ludlow and Rivington fully formed and fabulous. In conversation, she's chatty and articulate, but gives off the distinct sense she's 10 steps ahead of everyone else -- while the Internet is still buzzing about the lampshade she wore over her face in a TV interview, she's plotting her next move.

Of course, if she invests wisely, she may never need to work again: Her debut album, The Fame has sold nearly 1.3 million copies in the United States since its low-key release last September via Interscope. For the year, it's both the best-selling set for a debut artist, and the fifth-best-selling album overall.

Her digital single, Just Dance, has sold 4.4 million copies, according to Nielsen SoundScan, the No. 2 best-selling digital song of all time. Earlier this week, she snagged nine nominations at the MTV Video Music Awards, sharing the lead with Beyonce.

In addition to co-writing all the tracks on her album, GaGa has previously written for Fergie, the Pussycat Dolls, Britney Spears and New Kids on the Block.

Getting into writing for others happened naturally, because at the time, I didn't have a record deal, GaGa says. I don't have an ego about other people singing my songs.

And-as surprising as it may seem amid her outre outfits and the nudge-nudge-wink-wink lyrics-GaGa's path from behind-the-scenes songwriter to cultural phenomenon was a smart, regimented plan. Before she was Lady GaGa, she was Stefani Joanne Angelina Germanotta, an Italian Catholic schoolgirl from Yonkers, N.Y. She played piano and studied music as a child, but it wasn't until she hit her early 20s that her songwriting and performance style clicked.

She wrote almost all her hits in a week, says Vince Herbert, who signed GaGa to his Streamline Records label, a joint venture with Interscope. She flew to L.A. and sat in a studio with (producer) RedOne and just cranked it out.

GaGa writes mostly at the piano, and to her, if a song doesn't come easily, it isn't meant to come at all. A hit record writes itself, she says. If you have to wait, maybe the song isn't there. Once you tap into the soul, the song begins to write itself. And I usually write the choruses first, because without a good chorus, who really gives a f---?

But before she had hit records, she was an apprentice songwriter, working with a number of producers and trying to build a name for herself. Jody Gerson, who signed GaGa's publishing deal with Sony/ATV, points out that she was driven to understand the publishing business from a young age.

She interned at Famous Music Publishing before any of this, Gerson says. And even back then, she was famous for showing up for work in her undies.

GaGa says she doesn't want to be underestimated or written of as merely a pop songwriter. I think most music is pop music, she says. The mark of a great song is how many genres it can embody. It's about honesty and connection-look at a song like 'I Will Always Love You.' Whitney (Houston) killed it as a pop song, but it works as a country song, a gospel song, everything. If I can play a song acoustic, or just on the piano, and it still works, I know it's good.

Gerson says that she and GaGa are both particular about who the artist will work with, especially with her current touring schedule. She's swamped right now, Gerson says. There is a lot of interest; we're talking to (American Idol runner-up) Adam Lambert right now, for instance. But it has to be a good match for her to spend the time.

Coincidentally, GaGa's crowning TV moment came in April, when she performed Poker Face on the American Idol results show. While the show helped boost her album sales (according to Nielsen SoundScan, The Fame sold 45,000 copies the week before the show aired, 51,000 the week it aired and 56,000 the week after), more important, it showed middle America that she was a bona fide pop star.

GaGa gets plenty of additional screen exposure through the use of her songs in soundtracks and commercials. But deciding whether to align her with big brands has been trickier.

Steve Stoute, head of the branding agency Translation, thinks GaGa herself is a brand. To that end, he has signed a deal with her and says he will treat her just like he does such clients as McDonald's or State Farm. I don't just want to do deals for a check with her, he says. She's at the point where she's bigger than life. She's transcended music.

A few months ago, Lady GaGa decided to try a little experiment.

I was talking to the members of the Haus (her creative team) about the power of image and the camera, and I wanted to say something on a real level about fame, she says.

I drink a lot of tea, and I decided to take a purple teacup out of my china collection and take it to London and make it famous. I put it in videos and had fans pose with it and put it on TV -- at one point, the teacup had a call time. It became the most famous teacup since Meret Oppenheim covered one in fur.

Not surprisingly, GaGa has a background in art history, which she studied for a while at New York University before leaving to pursue music and performance full time.

There is certainly a performance art element to all of this, she says. I get challenged in interviews all the time, people asking me whether the clothes distract from the music. They're not separate; it's not one or the other. I dress the way I do to demonstrate my commitment to show business.

GaGa names as her inspirations people like Klaus Nomi and Andy Warhol, who she says saw themselves as living their roles. There is no sense of duality when it comes to who I am. It's not a play-acting thing for me. When I did the Rolling Stone cover shoot, I said I wanted to be shot as the rock goddess I know I'd eventually be.

Though she doesn't speak to it directly, there is a sense that GaGa also is canny about using her wardrobe to keep her in the public eye. In the month of July alone, Perez Hilton's Web site mentioned her 13 times, almost always for her outrageous outfits. More recently, Hilton's Twitter messages have been breathlessly recounting the pair's Japanese escapades.

Such attention is usually reserved for starlets going through rehab, involved in public breakups or falling drunkenly out of limos-and GaGa does none of this. Though she's admitted to using cocaine in the past, she seems to have realized that she can get just as much attention by slapping on a hat made of hair, without all the nasty side effects.

The Fame will be rereleased in the fourth quarter, a year after it debuted. It originally arrived September 9, 2008, to a mostly positive critical reception, but didn't appear on the Billboard 200 until November. It bounced around the charts for the early part of 2009, but then cracked the top 10 in March upon the strength of her first U.S. hit, Just Dance, and only built from there.

We always just assumed we were going to sell records, GaGa says. I have a sense of optimism and liberation, despite the state of the industry and the economy. We function like the industry is in full bloom, and that audacity works for us.

GaGa had to wait to hit those sales records in the United States, though, breaking first in Canada and then in Australia.

She has also toured nonstop, starting off opening for labelmates New Kids on the Block, then headlining her own Fame Ball tour. She opens for Kanye West later this year. And she can guarantee one thing-her closet will remain locked to the infamously stylish and demanding star. If Kanye tries to wear my clothes, I'll kick his ass, she says with a laugh.

(Editing by DGoodman at Reuters)