Old Crow Medicine Show [ tickets ], Dave Rawlings Machine featuring Gillian Welch [ tickets ], The Felice Brothers [ tickets ] and Justin Townes Earle [ tickets ] will join forces this summer for an outing dubbed "The Big Surprise Tour."

Each stop on the trek--which launches Aug. 4 in Hampton Beach, NH, and is scheduled to hit a total of nine cities by mid-month (details below)--will feature two 90-minute sets broken up by an intermission.

"In a free form ramshackle flow, the bands and artists will share the stage, taking part in each other's songs, resurrecting old standards, and playing newly written collaborative material as they go," organizers said in a press release.

"Seven years ago, when Old Crow first met Dave Rawlings and Gillian Welch at the Station Inn in Nashville, we stayed up till dawn singing Stan Rogers songs and playing AC/DC licks," Old Crow's Ketch Secor said in a prepared statement. "Three weeks later, we were making a record. They were that rusted sign at the fork in the road showing OCMS just where it was headed."

Old Crow Medicine Show continues to tour behind its latest album, last year's "Tennessee Pusher." The Felice Brothers's latest collection, "Yonder Is the Clock," hit stores in April. Justin Townes Earle's most recent set, "Midnight at the Movies," surfaced in March.

David Rawlings [ tickets ] and Gillian Welch are in the studio this summer "working on a Dave Rawlings Machine record which my never be released," according to a press release.