Beloved billionaire Warren Hellman knows a thing or two about putting on a music festival. After all, for 10 years he’s been the driving force and sole financial backer for San Francisco’s free Hardly Strictly Bluegrass Festival. Wednesday night, Hellman stepped out from behind the scenes into a different role, playing banjo as a featured performer at the South by Southwest Music Festival.

Hellman funds the entire Hardly Strictly Bluegrass Festival each fall as a gift to the city of San Francisco. An estimated 600,000 people attended last year’s festival as more than 60 acts played on six stages over three days. Past performers at “Hardly Strictly” have included Willie Nelson, Joan Baez, Lyle Lovett, Emmylou Harris, and Elvis Costello.

Hellman’s band The Wronglers — a play on Wrangler jeans, since Levi Strauss is San Francisco-based — formed, more or less, when they played at the Hardly Strictly Bluegrass Festival years ago.

“Our mantra is simple music played by complicated people,” said Hellman in an interview last year, of the Wronglers’ fusion of sweet sounds of fiddle, guitar, banjo and mandolin.

This year, the Wronglers have teamed up with legendary Texas singer-songwriter Jimmie Dale Gilmore to release the aptly named album Heirloom Music, a beautiful collection of classic songs from the '30s and '40s, due out May 3. And last night, Gilmore and the Wronglers made their first SXSW appearance together.

The period décor of the venerable venue for the South-by official showcase — the Victorian Room at the Driskill Hotel — couldn’t have been a better fit. Never mind that the hordes of SXSW celebrants traipsing down Sixth Street were clearly visible through the windows. Listening to Gilmore and the Wronglers, you could easily escape to a wonderful time long ago.

The high, lonesome sound of Gilmore’s expressive voice is a perfect fit for the “old time” music of the Wronglers. Sailing through lovely renditions of songs like “Time Changes Everything,” “In the Pines” and “Deep Ellum Blues,” the band delighted a crowd that overflowed the main room into the balcony.

Hellman, on banjo, was dapper in a sequin-spangled jacket and a tie once owned by banjo virtuoso Earl Scruggs (a gift from Scruggs’ son). The jacket, a present from his granddaughter, was emblazoned with sparkly Star of David motifs on each arm. (“Warren doesn’t wear his religion on his sleeve,” Gilmore joked.)

At the end of their set, Gilmore and Hellman traded lead vocals on a cheerful “Big Rock Candy Mountain," in which Hellman’s voice was reminiscent of the original version performed by the song’s author, Harry McClintock.

After the gig, Gilmore (and most of the Wronglers) headed down Sixth Street to catch the official SXSW showcase for his son, Colin Gilmore, himself a gifted singer-songwriter. Colin Gilmore just appeared in Houston last weekend for an acoustic set as part of a fundraiser for independent radio station KPFT Houston 90.1 FM. Wednesday night, a full band backed him as he rocked the Velveeta Room with songs from his latest release, "Goodnight Lane,"and literally had multiple Wronglers dancing in the aisles.

SXSW Continued: From the Badge-Free Zone

Over at Threadgill’s World Headquarters, Music Fog has been broadcasting great performances online all day long from artists like Guy Forsyth, Ray Wylie Hubbard and a reunion of Foster and Lloyd, who previewed new songs from their upcoming release It's Already Tomorrow. According to partner Jessie Scott, Music Fog will be streaming live every day for the rest of South-by.

More “found” music abounds everywhere. At the free 3rd Coast Music Showcase at G&S Lounge in South Austin, an outstanding line-up Wednesday included Terri Hendrix, quoting Woody Guthrie and (backed by Texas music stalwart Lloyd Maines on guitar and dobro) captivating the audience with a winsome performance. Following Hendrix, Jimmy LaFave (accompanied by a crack band featuring Andrew Hardin on guitar and Chip Dolan on keyboard) set the tone for what promised to be an outstanding evening.

No badge is required to check out Thursday night's official showcase at La Zona Rosa featuring Grammy-Nominated artist Janelle Monáe , Wiz Khalifa and B.o.B. online. The show is scheduled to be broadcast live starting at 9:30 p.m. on killerslaserspapers.com or via the SXSW website. (Alas, Cee-Lo Green is no longer able to perform at this SXSW showcase.)