Dave Grohl's recent trip to Seattle during which he went busking with Brandi Carlile apparently had more than performing outside the Pike Place Market on the agenda. In an interview with Rolling Stone, Carlile explained that she’s working with Grohl on a project but wouldn’t offer many details. She revealed, "I don’t totally want to give it away, but he came out to my house to talk to me about something he’s working on. It’s more like one of his doc-series."

Carlile and the Foo Fighters frontman teamed up earlier this month at the famous Seattle location to perform the Foos’ "Times Like These" and the Beatles’ "Let It Be." The Foos have been on hiatus since canceling a pair of February shows while Grohl recovered from arm surgery to repair a nagging injury.

Grohl has been getting into the documentary business for several years now, producing and directing a film about the legendary Los Angeles recording studio Sound City and creating a season-long HBO series, called Sonic Highways, that chronicled the making of the Foos album of the same name.

Grohl's mother Virginia also revealed late last year that a documentary about her son's life had started shooting, and both mother and son were reportedly developing a series based on Virginia's book of interviews with moms of musical stars.

Foos drummer Taylor Hawkins told us a while back that the band is always ready for whatever idea Grohl throws at them next: "The reaction when Dave comes to us with any idea is like, 'Okay.' You know, I know Dave and he has a lot of ideas. He's always thinking and he's always coming up with ideas, whether it's a funny T-shirt or an HBO series. He's creative and he likes to do stuff. He likes projects. He likes to work. And so whenever he says something that he wants to do, I say 'Hell, yeah.'"

The last Foo Fighters album, Concrete And Gold, came out in the fall of 2017 and was followed by a year-long world tour.

AUDIO: FOO FIGHTERS' TAYLOR HAWKINS ON DAVE GROHL HAVING BIG IDEAS