Trey Anastasio has penned a tribute to blues legend B.B. King, who passed away Thursday night at the age of 89. “It’s literally impossible to overstate B.B. King’s influence on every single electric guitarist who followed in his path. All of us who have ever bent a note owe him an enormous debt of gratitude,” Anastasio wrote. “When B.B. bent a note, it sounded like an amazingly soulful singer. He could shape it at will, and it sung out, like it was coming straight from his soul.”

King — his guitar, Lucille, in hand — made a surprise guest appearance at Phish‘s February 2003 concert in East Rutherford, New Jersey, joining the band for a trio of the late bluesman’s greatest hits, “Everyday I Have the Blues,” “The Thrill Is Gone” and “Rock Me Baby.” In true Phish fashion, the jammed-out performances of those three songs stretched to over 50 minutes. After nearly an hour of trading solos with Anastasio, King walked off the stage to a standing ovation.

“I was fortunate to have had a couple of opportunities to play with B.B. My favorite memory is of shooting the All Access IMAX film with B.B. King and the Roots,” Anastasio added. “In between takes, we all started jamming, just making stuff up, and there was one particular moment where it just got so, so good. B.B. was absolutely cooking on the guitar, Questlove and the rest of the Roots were grooving so deeply, and I was standing right next to B.B. trading licks. I was in heaven.”

For that IMAX film, both Anastasio and the Roots served as King’s backing band on “Rock Me Baby.” “I’ll never ever forget that moment. I looked over at B.B. and he had that little smile on his face, and I just thought, ‘What an incredible guy, to take a moment to play music with these young musicians, all of whom completely idolized him,'” Anastasio said. “He was just one of the boys playing the guitar for a moment there. I learned so much from that experience.”

Anastasio joins Eric Clapton, ZZ Top’s Billy Gibbons and Presidents Barack Obama and Bill Clinton as one of the many famous fans who have paid tribute to the late bluesman.