For kids of the 80s, there are few theme songs as kick-ass or roller-rink ready as Ray Parker Jr.’s classic ode to how bustin’ makes him feel good. But thanks to a new documentary, we know that Parker wasn’t totally on board with the concept or the execution.

Upcoming rock documentary Hired Gun chronicles the lives of session musicians, the unknown heroes behind some of the biggest bands, including Metallica, Nine Inch Nails, KISS, Ozzy Osbourne, Alice Cooper, and more. Following in the tradition of docs like Standing in the Shadows of Motown, these behind-the-scenes explorations of the men and women who made our favorite songs can be absolutely heartbreaking — especially since few musicians get the compensation or fame they deserve. Hired Gun seems to be a more upbeat take on this category.

The film premieres this Friday at SXSW, and to celebrate, producers released this clip of Ray Parker Jr. mapping the origins the of Ghostbusters theme song — the result of a three-day work bender and a very direct prompt from his director.

Check it out below: