Pulp's 1995 headline slot has gone down in history as one of Glastonbury's most memorable and triumphant sets - but it was actually a last-minute booking, after Stone Roses guitarist John Squire broke his collar bone.
Cocker later revealed "it was the most nervous I've ever been in my life".
"But then Robbie from Take That came and wished us luck," he told Vox magazine.
"Robbie read us some of his poetry. I was dubious at first, because sometimes poetry can be embarrassing, but it was really good."
The performance came just a couple of weeks after the release of what would become their signature song, Common People.
With the anthem lodged at number two in the charts, the band held it to the very end of their set for maximum impact.
As he introduced the track, Cocker gave a heartfelt speech about the band's slow-burn career.
"If you want something to happen enough, then it actually will happen – and I believe that," he said.
"In fact, that's why we're stood on this stage today after 15 years, because we wanted it to happen, do you know what I mean?
"So if a lanky git like me can do it, you can do it too."
And with that, they launched into a celebratory, communal, 7-minute singalong that confirmed Pulp's status as the poet laureates of Britpop.
"That was the event that made the success a concrete fact," Cocker later told Radio 4's Desert Island Discs.