Today's installment of The Boot's Grace & Tony Greenroom Sessions series was a chance for the "punkgrass" duo to venture into the wilderness with UK folk duo the Black Feathers and cellist Chris Wilson. The song, 'Open Book,' is a Black Feathers original.

"We grabbed a spot near our home. I had discovered this cave years ago in the Saint Joseph, Tenn. city park and thought it would be a cool location," Tony tells The Boot. "Turns out the acoustics were amazing!"

The two groups have toured together in the past, but they recorded this particular Greenroom Session during the Black Feathers' recent U.S. tour.

"We have been friends ever since we met on Twitter, and they booked an entire tour for us in the UK last summer," Tony says. "Needless to say, they are great friends."

Grace & Tony's daughters, Alli and Mary, are fans of the Black Feathers too, so their parents gave them the chance to get involved. Mary served as guest vocalist, while Alli handled filming the session.

"They are huge fans of Ray and Sian's music and really look up to them," says Tony.

September will bring two new Greenroom Sessions videos to The Boot, so be sure to check them out on the 1st and 15th!