In the '80s Willie Nelson, Waylon Jennings, Kris Krisofferson, and Johnny Cash - four of the biggest stars in America - joined forces to form a true country music super-group, and revolutionize American music.

The "super-group" will be the focus of a new PBS documentary titled The Highwaymen: Friends Till the End, that will premiere on PBS on May 27th, 2016. Set those DVRs now.