Plant went on to co-found Led Zeppelin, while the promoter in question, Rod MacSween, co-founded International Talent Booking and became one of the world's most successful talent agents.
Despite stiffing the rock icon Plant more than 50 years ago, the two have remained friends. So when MacSween was recently awarded an honorary doctorate from the University of Exeter, he told students during his speech that it was finally time to honor the debt.
The university reported that MacSween then invited Plant onstage during commencement to collect a £10 note.
A smiling Plant arrived on stage and joked that £10 wasn't enough. In a moment of sincerity, he added that he had enjoyed "sharing my adventures" with MacSween.
A photo from the afternoon shows MacSween in graduation robes next to Plant who is clutching the £10 bill in his hand.
Photo: Getty Images