They’re funnier than they look. And they are seasoned performers not even 30 years old.

After he heard “Bartender’s Advice to the Urban Cowboy Blues,” singing legend Willie Nelson said to the Ginn Sisters, “That’s a great song! Can I hear another one?”

Born and raised in Texas, Tiffani and Brit Ginn grew up in The Pettit Family Band, whose rule was “find a part and join in — no excuses.” The two made parts for themselves in folk, country, bluegrass and old-time tunes while Brit learned to play the flute and Tiffani learned guitar and dance.

They cite not only folk and country greats but Bob Marley as influences on a style that’s moved toward greater eclecticism. Their 2006 CD “Blood Oranges” was played on acoustic Americana, folk, country and bluegrass radio. Asked whether they find their songs and performance style changing in any particular direction, Brit says that they go through phases.

What remains constant, though, is the harmonies that a bar owner in Gonzales called “the hottest in Texas” — and the onstage chemistry of sisters who’ve been performing together for years. Tiffani writes most of the songs after she and Brit talk through the journeys they’ve made together.

This summer’s journey includes new features. Tiffani and her husband sold their house before this tour began—and they’re traveling with their baby.

After their appearance at the United Center on Saturday night, the Ginns will spend the summer working with Fred Eaglesmith, who appeared at the United Center in January.

“Of course we love the freedom of putting on our own show,” Brit says. “But there’s something so fun about being on a full stage with great musicians. And we’ll be opening for Fred as well.”

Then, this fall, they plan to work on finishing a new CD.

In returning to Idaho Springs, the Ginns look forward to the intimate, “almost magical” atmosphere of the United Center and the great audience. They also enjoy the chance to catch up with friends in the community, including United Center board member Bob Hickam.

Find the Ginn Sisters on the Web at www.theginnsisters.com.