If the music of Pink Martini sounds like it comes from an imaginary Rita Hayworth movie set in a sultry St. Tropez nightclub, then the band's creator has succeeded in his quest.

By his own admission, Thomas Lauderdale, founder, songwriter, and pianist for the 12-piece Oregon-based ensemble has put together a band that sounds like ''Mary Poppins meets the United Nations." To be more specific, the recipe for a Pink Martini would read something like this: One part French chanson, one part Argentine tango, one part soft merengue beat, and a dash of gin-joint jazz. Combine ingredients and shake vigorously over old Hollywood glamour. Pour into a glass and garnish with a paper parasol.

There is no simple way to generalize the international sound of Pink Martini, but the band's aesthetic is easy to determine. Lauderdale, 34, grew up with a strong love of old Hollywood films, the kind that featured well-coifed leading ladies, their mouths caked with deep red lipstick, being pursued by handsome men who didn't skimp on the Brylcreem.

Lauderdale isn't a starry-eyed sentimentalist who lives in a mythic celluloid past, but he can't help but invoke titles such as ''Auntie Mame" and ''Breakfast at Tiffany's" when describing the inspiration for his sexy, cocktail-hour music.

''I think each of us hopes for all kinds of amazing, magical things to happen in our lives, just like those old movies," Lauderdale says on the phone from his home in Portland. ''Everybody wants to be fabulous."

Pink Martini's beginnings, however, were anything but. The band, which plays four shows with the Boston Pops this week, started as a result of the many dull political fund-raisers that Lauderdale attended in Portland. These may have been parties for progressive causes, but he found both the lighting and the music bleak. So he set out to create a band that he would want to hear at a political event.

This was all intended as a side project. Lauderdale's true ambition was to become mayor of Portland.

''The whole concept of having a band was truly the last thing I ever expected to be doing," he says. ''I grew up studying classical piano, but I went off to Harvard to study history and literature with the intention of going into politics. The band was going to be a one-time thing, and, well, here we are."

Lauderdale's one-time thing took on a life of its own after he drafted his Harvard buddy China Forbes to sing with Pink Martini. Her buttery voice is ideal for the band's songs and keeps them from drifting into cloying territory. After convincing Forbes to move to Portland from New York, the band recorded 1997's ''Sympathique," an album primarily made up of midcentury covers that sound vaguely European and South American.

Eight years later, the independently released album from the unclassifiable band from Oregon has sold more than 700,000 copies.

Most of those albums were sold in Europe, where Pink Martini's discs have gone gold and platinum. France is a particularly strong market, especially when the band scored a summer hit with the title track of ''Sympathique" after the song was used in a Citroen car commercial. The band's most recent album, ''Hang On, Little Tomato," is frequently on the French version of iTunes' most-downloaded-albums list and recently finished a long run on the French album charts.

''I think people have a different perspective on us in other countries," says Lauderdale. ''In every other country there's this history of singing and dancing together. Everybody plays an instrument, and there's also a sense of history about all of it. In town centers through Italy, you have couples in their 80s sitting next to teenagers, and there's a constant dynamic exchange.

''In this country, there's a lot of division. Certainly with older people. I think what comes out of that is a loss and a lack of history."

Pink Martini's music not only spans several languages, its live shows also attract a multigenerational fan base seldom seen at pop concerts. Lauderdale says he sees the broad audience as a result of his band's revisiting a different era, but from a modern perspective.

In this country, Pink Martini is perhaps best known for its collaborations with orchestras. The connection began when Lauderdale was 13 and won a classical music competition. A classical piano prodigy, he appeared regularly as a solo pianist with the Oregon Symphony Orchestra. Years later, when Pink Martini began developing a cult following in Portland, the conductor remembered the piano prodigy and asked the band to perform with the orchestra in 1999.

Lauderdale sees the pairing of his band with symphonies as a natural fit, because many of the band's songs evoke the sense of a Hollywood musical, and a string section only enhances the feeling.

Boston Pops conductor Keith Lockhart heard the band collaborate with the Utah Symphony. Lockhart, who serves as that symphony's music director, wasn't conducting, but from his seat in the audience he was impressed enough to bring the ensemble to Boston.

''One of the things that makes these songs work in an orchestral setting is that the band is made up of really good, accomplished, and classically oriented musicians," Lockhart says. ''The orchestra just really adds beef and body to what they're already doing.

''Sometimes," he adds, ''when you bring in an electronically based pop act with the orchestra, it's so apples and oranges that it doesn't matter if the orchestra's there or not. But this is a real acoustic act. I thought it was immensely effective as an orchestra show."

The benefit for orchestras is younger audiences. The benefit for Pink Martini is an opportunity to tour the country. With 12 members who play instruments such as harp and upright bass, the band is unable to pile into a van and drive across the country to play in dingy rock clubs. Especially since there is no label to finance a tour. Pink Martini releases its music on its own label, named after Lauderdale's dog Heinz.

''It's almost like we're this old-fashioned band from 'Some Like It Hot,' where everybody has big luggage, travels in sleeper cars, and expects to stay in fancy hotels," Lauderdale says. This week's Boston shows are the first time the band has played in the area in four years. The last time Pink Martini came through Boston, its 12 members were crammed onstage at the Paradise Rock Club.

But despite only moderate success in the American market, Lauderdale sounds optimistic about Pink Martini's chances of reaching a wider audience. In fact, he's sounding almost as optimistic as Mame Dennis during the market crash of 1929.

''We record in different languages and we mine many different styles of music," he says. ''But ultimately everybody's curious about the world, and I think that's why people continue to be interested in our music."