In a new interview with Relix, Amir Bar-Lev, the director of the four-hour Grateful Dead documentary Long Strange Trip talks about bringing the film to life including a rare cameo from Robert Hunter that Bar-Lev says was years in the making.

“I went through years of petitioning him—petitioning people he knows—and was preparing for him to be a cipher in the film,” Bar-Lev says. “I would ask people on camera whether or not they thought I could get him and why he didn’t want to be on camera, and I almost satisfied myself that his absence could be made to work for the film.”

Bar-Lev says the breakthrough came when speaking one night with Bob Weir. “He offered to call Hunter and bring us over there that very evening. And the result—I’ll leave to the audience to see.”

The director also dishes on his own Grateful Dead fandom, saying he got into the band as a 13-year old growing up the Bay Area. “I started seeing shows in the mid-80s. Those of us who got into the Dead in the 80s found a sanctuary from some of the more superficial aspects of the culture at the time.”

“For a while, it ruined other bands for me. Once you’ve been to a Grateful Dead concert, and then somebody’s saying, ‘Hello, Cleveland!’ and doing that kind of schmaltzy rock-and-roll stuff, you see it for what it is—a piece of showbiz.”

Long Strange Trip will come to theaters for one night only beginning May 26 and Amazon Prime will release the film on June 2.