Actor and beloved comedian John Belushi would have celebrated his 70th birthday today. Best known for his tenure as an original cast member of Saturday Night Live and his roles in iconic films like Animal House and The Blues Brothers, Belushi was one of the most magnetic personalities of his generation, even attracting the likes of the Grateful Dead, particularly drummer Bill Kreutzmann.

In his 2015 book, Deal: My Three Decades of Drumming, Dreams, and Drugs with the Grateful Dead, Kreutzmann recounts the great friendship and some of the wild times he shared with Belushi when the Dead used to get out to New York City. One such instance occurred during the Dead’s opening night at the now-defunct Capitol Theater in Passaic, NJ on March 30th, 1980 when Belushi got it into his head that he wanted to sing backup with the band on “U.S. Blues” during the encore. However, met with some resistance from the band, Kreutzmann had to nix Belushi’s wishes. Belushi had other plans.

Kreutzmann writes:

I had a really good show that night, and the entire band played well. We encored with “U.S. Blues” as planned and, right before the chorus, Belushi took everyone by surprise by cartwheeling onto the stage. It was a comedic ambush. He had on a sport coat with small American flags stuffed into both of his breast pockets and he landed his last cartwheel just in time to grab a microphone and join in on the chorus. The audience and everyone in the band – except for Phil – ate it up. It couldn’t have been rehearsed better. Belushi had impeccable comedic timing, musicality, balls, the works. And apparently, he didn’t take no for an answer.

Take a listen to the Dead’s entire March 30, 1980 performance with Belushi helping out on vocals during the “U.S. Blues” encore:

The Grateful Dead – 3/30/80 – Full Audio