The Greencards will make an appearance at Bluegrass Underground near McMinnville, Tenn. in August. Photo by David McLister.

The Greencards with the Two Man Gentleman Band will perform at 1 p.m. Aug. 1 at Bluegrass Underground, a live concert and radio show held inside the Volcano Room, which is a natural amphitheater 333 feet underground in Tennessee’s Cumberland Caverns.

The caverns, a registered US National Natural Landmark, attract thousands of visitors from around the world year-round. First discovered in 1810, Cumberland is Tennessee’s largest show cave. It offers daily walking tours, spelunking adventure trips, overnight camping — and now monthly bluegrass shows — in the cave.

The Greencards, a multi-national trio, have a new Sugar Hill Records release that showcases the band’s fascination with American roots music. Members include basis Carol Young, multi-instrumentalist Kym Warner and violinist and violist Eamon McLoughlin. They have toured with Bob Dylan and Willy Nelson and, in 2008, received a Grammy nomination for Best Country Instrumental Performance.

Hailing from New York City, The Two Man Gentlemen Band combines hot jazz, vintage rhythm & blues, old-time country, and Tin Pan Alley to create a two-man sound that is all their own. Performing with plectrum banjo, guitar, string bass,dueling kazoos, novelty percussion, and a cornet, The Gentlemen whip themselves into a frenzy that is unlike any acoustic duo on the road today. And they belt out original songs that manage to be at once familiar, bizarre, fun and entirely new.

Bluegrass Underground is taped once a month, and tickets can be purchased at the Web site, www.bluegrassunderground.com.

Bluegrass Underground shows can be heard on 650 WSM and online at wsmonline.com each Saturday night from 5 to6 p.m. Bluegrass Underground is also aired on Thunder Radio WMSR-AM in Tullahoma, Tenn., each Saturday at 2 p.m.

Cumberland Caverns is located in the heart of Middle Tennessee, centrally located between Nashville, Chattanooga and Knoxville. The cave is just off of Highway 8, six miles southeast of McMinnville via US 70-S, between Nashville and Knoxville, or via Highway 55 from I-24 at Manchester, between Nashville and Chattanooga.