When Pink Martini—the old-fashioned, global-symphonic pop hybrid that will close the 2011 Ann Arbor Summer Festival' main-stage series—takes the stage Saturday night they will be without founding vocalist China Forbes.

Not to worry, however, as another West Coast powerhouse, vocalist Storm Large, has been filling in as needed. “She’s fantastic,” co-founder Thomas Lauderdale said. National Public Radio journalist-turned-singer Ari Shapiro will also be performing with the band.

Forbes recently took a long-term leave of absence from the Portland, Ore.-based group. She needs surgery on her vocal cords, according to an announcement from the band.

The 12-member, Portland, Ore.-based group was founded in 1994 by Lauderdale, a Harvard graduate and classically trained pianist, to play political fundraisers for progressive causes. He met vocalist Forbes while they were at Harvard. They began to write music and lyrics together and their first song, the bouncy "Sympathique"—with the chorus “Je ne veux pas travailler”(”I don’t want to work”)—became an overnight sensation in France.

"Our success was totally a fluke; I thought I was going to go into politics," Lauderdale said.

Although from his perspective it’s hard to tell if the band is broadening its popularity or not, he allowed that audiences “have been incredibly loyal and I’m encouraged that there are young rock and rollers who find their way to the band and like it.

“In the end what seals the deal is live performances and the audiences have been—despite the devastation in American culture in general—coming back, and growing and that’s encouraging,” he added. “I feel lucky to be able to play music and to make a living and to not have been working under fluorescent lighting from 9-5.”

Vocalist Storm Large first became known in Portland as the leader of Storm and the Balls. She gained national prominence in 2006 as a finalist on the CBS show "Rock Star: Supernova." Also a stage actress, jer autobiographical musical memoir, "Crazy Enough," enjoyed a 17-week run in Portland. Large recently performed the show at the Edinburgh Fringe Festival and Joe’s Pub in New York.

Since its early days, the group has performed its multilingual repertoire on concert stages and with symphony orchestras throughout much of the world. "Sympathique" was released in 1997, "Hang On Little Tomato" in 2004, "Hey Eugene!" in 2007 and "Splendor In The Grass" in 2009. In November 2010, the band came out with "Joy To The World"—a multi-denominational holiday album featuring songs from around the globe.

The success of the Christmas CD, commissioned by and sold at Starbucks, has helped spread the Pink Martini sound, Lauderdale said.

“It ended up in five weeks outselling both of the previous two albums we had released. Now I understand why it is people release holiday albums. And I think it’s one of the best albums we’ve released.”

Even though the Ann Arbor show is in July, there could be a selection or two from the album included in the set. “The Chinese New Year song is really interesting, and ‘Auld Lang Syne’ should be played year-around. If we ended all of our days with ‘Auld Lang Syne,’ the world and this country would be a better place,” he added.

Meanwhile, Lauderdale and the band have been busy producing an album for Japanese singing superstar Saori Yuki (she performed “White Christmas” on the Christmas album) that is due out in the fall (look for a version of “Puff the Magic Dragon” in Japanese).

Lauderdale said he has fond memories of performing in Ann Arbor.

“I grew up in Indiana just across the border, so I appreciate the Midwest very much. In Ann Arbor the last time I discovered the Maya Lin sculpture (The Wave Field) at the University of Michigan—it’s amazing. The last time it was also amazing that (multiple Grammy Award-winning composer and Ann Arborite) William Bolcom was in the house.”

Summer Festival Director Robb Woulfe said the popularity of Pink Martini has been growing, especially in Ann Arbor, citing their move from Power Center to the much larger Hill Auditorium. “I think in the Midwest, people are finally discovering the allure of Pink Martini … their presence is becoming a little more commercial in terms of where some of their music is played. It’s not just tucked on public radio stations anymore.

“I love that we’re closing the season out with them; they are such an amazing group and they have such a wide appeal,” Woulfe said. “The young hipsters love them, some of our older festival goers just love them. I love seeing the audience at Pink Martini—it is such a beautiful mix of people.”