Following his success with the 2013 documentary Sound City, Dave Grohl decided to chronicle Foo Fighters‘ cross-country trek to record songs for their eigth album, due in November, in storied studios in eight musical cities. Among the cities he visits are Austin, Chicago and the home of country music, Nashville.

The upcoming eight-part HBO series, Foo Fighters: Sonic Highways, will premiere on the pay cable network in October and features Grohl interviewing scores of musicians — and even President Obama — about the music of their cities. In each place, he collaborates with native artists and then writes a song. He calls the series “a love letter to the history of American music.”

At an HBO event to promote the show in Beverly Hills on Thursday, Grohl discussed recording at Zac Brown Band’s Southern Ground Studios in Nashville this spring and the surprise appearance he made at the famed Bluebird Café to play a few Foo tunes. The rocker admits it was a daunting prospect to perform at the revered country songwriters’ haven.

“The Bluebird I knew a little bit about, but I learned a lot,” Grohl says of the unannounced appearance at the intimate venue. “In Nashville it seems like there are these rites of passage that you have to go through to become a star, whether you’re a singer or a songwriter, and the Bluebird is really one of those. If you can get down at the Bluebird, you’ve got a gig.”

Other country stars set to be featured in Sonic Highways include Willie Nelson and Dolly Parton, of whom Grohl says, “Nobody is cooler than Dolly Parton. Her story is amazing.”

Grohl’s ties to Nashville have been growing increasingly strong in recent months. Last year, he produced the Zac Brown Band’s EP The Grohl Sessions, Vol. 1 and performed with the group during November’s CMA Music Awards.