Before Grateful Dead vet Bob Weir joined the Avett Brothers onstage at this year's Mountain Jam for a set that included a cover of country legend George Jones‘ 1964 hit ‘The Race is On' and a run through the Avetts' own 'Go to Sleep,' they had to iron out some of the wrinkles with a bit of prep work -- and now you can watch them rehearse, thanks to some new backstage footage posted at the Mountain Jam website.

In the five-minute clip embedded above, you can watch the Avetts lead Weir through an early attempt at 'Go to Sleep,' and although it's clear they're all still getting a feel for how the performance will ultimately work, fans should find it an interesting glimpse of the collaborative process at work. After you've watched the rehearsal, you can catch some of Weir's time on stage with the Avetts (as well as a portion of their main set) right here.

Since playing Mountain Jam, Weir has spent the rest of the summer touring with his band Ratdog, tackling an ambitious itinerary that's currently slated to keep them on the road through mid-September.