How cool are the musicians of Pink Martini? So cool that even blood kin of the famed von Trapp singing family will come out of semi-retirement for a chance to perform alongside them.

On Thursday night, the Utah Symphony will present “Joy to the World” at Weber State University in Ogden. The concert will feature the Salt Lake City-based symphony orchestra joined by Pink Martini, a 12-piece musical group from Portland, Oregon, that performs classical, classic pop, Latin and jazz from around the world.

In the past, founder/bandleader/pianist Thomas Lauderdale has referred to Pink Martini as a “rollicking around-the-world venture,” explaining that, “If the United Nations had a house band in 1962, hopefully we’d be that band.”

For this week’s Utah shows (they’re also performing with the Utah Symphony on Friday and Saturday at Abravanel Hall in Salt Lake City), Pink Martini will have a host of special guests in tow, including the aforementioned von Trapps, a sibling quartet that traces its roots back to one of the most famous singing families in the world.

The von Trapps are the great-grandchildren of Captain and Maria von Trapp, who were immortalized in the 1965 musical “The Sound of Music” starring Julie Andrews and Christopher Plummer.

“Our grandfather was portrayed as Kurt (the younger son) in ‘The Sound of Music,’” Melanie von Trapp said Tuesday in a telephone interview from Pittsburgh, where she was visiting her boyfriend. “That’s how we’re related to the family.”

Melanie von Trapp — along with siblings Sofia, Amanda and August — began singing together in 2001, when the now-28-year-old was just a young girl. They’ve been singing professionally for the past 15 years.

“We grew up singing together, but we never expected we would try to sing professionally or carry on the tradition,” said von Trapp, who was raised in Montana. “We just loved music, and our parents thought it was a fun thing for the family to do together.”

When their grandfather, who lived in Vermont, had a stroke, he couldn’t visit his grandchildren, who lived in Montana. So the four youngsters recorded the songs they used to sing with him so he could listen to them in the hospital.

“Someone heard the recordings we’d made and asked us to open for them,” von Trapp recalls. “That’s how we started doing shows locally.”

In the beginning, the von Trapps sang old folk songs from Germany and elsewhere. Then, in 2011, they met Thomas Lauderdale and Pink Martini.

Lauderdale invited them to come to Portland and record music with his group. Recording an album was supposed to take two weeks, according to von Trapp. It ended up taking two years.

“It was a really fun process, and very experimental,” she said. “Pink Martini is an amazing group, and Thomas has such an ear. We’d sit in his studio and listen to old records from all over the world, or go to record stores and hunt down old, obscure folk music.”

The von Trapps eventually relocated to Portland from Austin, Texas, and began working and touring with Pink Martini.

Von Trapp says Lauderdale was just what she and her siblings needed. They’d spent 10 years together as a children’s group, and they were looking for someone who had a vision they could share.

“Thomas just took us under his wing and we became such good friends,” she said.

Von Trapp said she and her brother and sisters have had to find that balance between honoring the legacy of the von Trapp family name and leaving their own mark in the world.

“It’s important for us to come to a good balance between incorporating that — this legacy we have — and remembering that we’re Melanie and Sofia and August and Amanda,” she said. “We’re trying to have a balance, but it’s always a struggle.”

The von Trapps have been on something of a hiatus for the last 2½ years while they pursue schooling and careers and other interests. Von Trapp said being a full-time musician does take its toll.

“It’s a fairly demanding job to be full time in music, and we’ve been doing it since I was 11, so we wanted a bit of a break,” she said.

The four singers are not quite ready to get back together full time, but von Trapp says they always “jump at every opportunity” to sing with Pink Martini.

“I think it hasn’t been quite long enough to feel the absolute urge yet, but I do — all of us — miss singing together,” she said. “It’s so much fun.

The exciting thing about the Utah shows, according to von Trapp, is all the guests artists who’ll be appearing with Pink Martini. In addition to the von Trapps and a couple of artists from Portland, guest vocalists will include Ari Shapiro (who has an “amazing voice,” according to von Trapp) from NPR’s “All Things Considered,” as well as Katie Harman Ebner, the 2002 Miss America.

Expect a “very upbeat party vibe,” according to von Trapp.

The “Joy to the World” concert will primarily feature holiday songs, but von Trapp says they’ll do some others as well — from all over the world.

“I like coming to these shows, especially this one with Pink Martini,” von Trapp said. “Seeing the look on everyone’s faces when we all sing ‘Brazil’ at the end of the night, or when there’s a conga line — there’s just so much positivity and everyone is smiling that I always feel elated after these shows.”

Von Trapp said almost every song at the concert will be in a different language, although the musical arrangements share enough in common that it creates “a feeling of similarity that blends together in a magical global experience of music.” She gives Lauderdale all the credit for this feeling.

“He has a huge heart, he’s a generous person, and he believes that everyone can find some common ground,” she said. “And ethnic music is one of those special things that creates a platform to connect with people. (This music) is a way to create a culture where people can enjoy the fact that we’re all humans.”

Contact Mark Saal at 801-625-4272, or msaal@standard.net. Follow him on Twitter at @Saalman. Friend him on Facebook at facebook.com/MarkSaal.

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