"The Larry Sanders Show" star died in March after suffering a heart attack, and he was remembered onstage during an unexpected appearance by Vedder at the festival's Comedy Theatre, reported Contactmusic.
Taking the stage during Apatow's set, which took place before his band Pearl Jam's headlining gig, Vedder debuted a special song he had created from Shandling's writings as he strummed on an acoustic guitar.
The "Knocked Up" filmmaker filled in the gaps by recounting quips from the late actor's own journals, which included lines like, "My friends say I have an intimacy problem, but they don't really know me," and, "My mum wants me to have kids - just not with other people," according to The Tennessean.