Jason Isbell and his band, the 400 Unit, played Atlanta's Sweetwater 420 Fest on Sunday (April 21), taking the stage just before jam band mainstays from nearby Athens, Widespread Panic. The event created an opportunity for Isbell to lend a helping hand during Panic's cover of ZZ Top's bluesy standard "Jesus Just Left Chicago."

Isbell, a former guitarist for Athens' Drive-By Truckers, fit right in with the fellow students of roots music. As the all-star jam reached its crescendo, Isbell's guitar interplay with Jimmy Herring taught non-fans an important lesson: The former is way more than just a talented wordsmith. Readers can press play above to watch the performance.

Their jam at Sweetwater 420 Fest wasn't the first time that Isbell has taken the stage with Widespread Panic: The Deep South dream team previously performed JJ Cale's "Ride Me High" during a 2016 show in Raleigh, N.C. Both acts play are scheduled to play the Ride Festival in Telluride, Colo., in July, so there's a chance there won't be another three-year delay between live collaborations.

Sweetwater 420 Fest is an annual event that features both jam band royalty and some of Americana's top stars. Besides Isbell, the lineup for this year's even, which took place April 19-21, included Aaron Lee Tasjan and the Avett Brothers.

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