Delta Rae performs on Saturday night at 9:30 Club.

Sibling relationships have been the foundation of musical success for as long as rock and roll has existed. From the Everly Brothers to The Staple Singers to Van Halen, talent that was cultivated in living rooms grew into a pathway to stardom.

Delta Rae is another example of fame coming out of the connection between brothers and sisters. The sextet out of Durham, N.C. started with singer-songwriters Ian, Eric and Brittany Hölljes. The band has grown since its humble beginnings, but now Delta Rae is selling out clubs across the country, including tomorrow night’s show at the 9:30 Club, and is poised for even greater stardom.

“From the outside it looks like that, but we haven’t felt like that internally,” Ian Hölljes recently told DCist. “We’re still racked with insecurity and worries about how things are happening.”

Hölljes recalled how Delta Rae had visited the District a number of times, playing venues like the Rock and Roll Hotel where only tens of people would be in the audience. Things changed when the band made its major label debut in 2012 with the release of Carry The Fire. The single, “Bottom of the River,” caught on and, with the help of the label, the band started landing slots on the festival circuit. While the clout of Sire Records no doubt helped, part of the credit goes to the band’s own evolution. Starting out as a vocal quartet with the occasional hand percussionist, Delta Rae added a drummer and bassist, allowing the sound to grow out of its Americana roots and bringing in more soul and rock elements. While Ian and Eric Hölljes are the chief songwriters, the other vocalists — Brittany Hölljes and Elizabeth Hopkins — also determine the direction a song takes.

“We work very naturally together,” Hölljes said. “We seem to write in a way that allows each member to take a song while we’re writing. Because the song resonates, they kill it.”

Hölljes feels like the group has again broken new ground with its 2013 EP, Chasing Twisters. The title track brings a heavier rhythm section and guitar sounds to drive the multi-part harmonies for which Delta Rae is known. The release also features a re-recording of “If I Loved You,” a song first issued on Carry the Fire, but this version includes Fleetwood Mac’s Lindsay Buckingham as a special guest. This is only fitting, given that Delta Rae has been known to cover “The Chain” in its live concerts and also mirrors the Fleetwood Mac style of layered vocals over a rock solid rhythm section.

This new direction is indicative, Hölljes feels, of the material Delta Rae has recorded for an album that will likely come out later in 2014. Until then, the band will continue to hit the road, as it has been continuously doing for the better part of five years. Hölljes also believes that this work ethic and the band’s new direction will only cement the bond with its growing audience.

“Our music is coming from a heartfelt place,” he said. “If you go at it in a very emotional way, even if it’s about death or loneliness, the connection you build is one of exhilaration and happiness. That would be my hope.”

Delta Rae performs on Saturday, February 15, 2014 at 9:30 Club with opener, The Falls. Tickets are sold out.