The Zac Brown Band might be one of the most successful bands in country music, but they're quickly gaining universal appeal. Their latest single, "Heavy Is the Head," from their upcoming Jekyll + Hyde album, has earned them a spot on Billboard's Mainstream Rock Songs chart.

The single, which includes guest vocals by rocker Chris Cornell, first debuted at No. 37 on the chart in early March; now, in its fourth week on the Mainstream Rock Songs chart, it sits at No. 5.

"In looking for new music, I look for what stands out, and this, for sure, does," Vinny Usuriello, program director of SiriusXM's hard rock channel, Octane, tells Billboard. "It's got a little country in it, but I feel rock overpowers it. It definitely fits our format."

The Zac Brown Band are no stranger to collaborating with rock stars. They released an EP, The Grohl Sessions: Vol. 1, with Foo Fighters frontman Dave Grohl in 2013.

“We’re all continuing to grow up and get better as musicians, and the chemistry as a band continues to deepen,” Zac Brown says. “Our boundaries have dissolved, and we’re going to still do things that are somewhat familiar that people like, but we’re also going to stretch out and take chances beyond what we’ve done before. Some people are going to be really surprised.”

The ZBB performed "Heavy is the Head" on Saturday Night Live last month. They also played "Homegrown," the album's first single, which has earned the top spot on Billboard's Country Airplay chart this week as well.

Jekyll + Hyde will be released on April 28. It is currently available for pre-order on iTunes and Amazon.

See Zac Brown's Yearbook Picture!