When Diana Ross plays Glastonbury on Sunday afternoon, her warm-up act will be a DJ who spends the rest of the year working in a job centre in Stroud.
Chris Bull has been the Pyramid Stage DJ since 1983, when tickets cost £12 and the headliners included UB40 and US singer-songwriter Melanie.
"It's a bit bizarre, isn't it?" says the 68-year-old.
"But it shows that this festival is for everyone. No matter what you do, you can come here and have a good time."
Bull got his big break in his 20s, when he worked at a record shop in Bristol.
A Glastonbury regular, he knew the festival was looking for a DJ and, through an acquaintance, asked Radio 2's Johnnie Walker if he'd be interested in the gig.
"And he said, 'Brilliant, but you'll have to do it with me 'cos I haven't got any gear'," Bull recalls.
"That's how it all started. There've been changes over the years but I guess I'm still here."
Over the last four decades, he's played tunes between sets by Dolly Parton, Elbow, the Sugababes, Sheryl Crow, Foo Fighters, Blondie and Coldplay.
But the one that really stands out is Kanye West who, unlike most headliners, let the resident DJ warm up his audience.
"I thought, 'How strange, here I am playing music before Kanye West,' but I thought I did a good set. Mostly old-school stuff, not the latest and greatest, but I had a go."
Despite his proximity to rock's biggest and brightest, he says he rarely gets to fraternise with the stars.
"To be honest, when they've done their sets, they leave," he says. "The Rolling Stones had a whole area where they hang out, and yours truly doesn't get to go there."
But he did meet his hero, Mike Scott of The Waterboys, when they played the Pyramid Stage in 1989 - and even got the singer to autograph his ticket.
"And I bumped into John Peel in the urinals," he adds.
Like many of Glastonbury's long-serving crew, the festival is intertwined with his family life. His son Liam first attended the event as a baby in 1987. This year, Liam will be cheering on his dad alongside his new wife, Anna.
With one day to go, Bull says he hasn't planned what to play yet, saying he prefers to read the crowd before deciding on a setlist.
"I'll be there and setting up in the morning, and then sounds will start playing," he says.
And after 39 years, this is still his favourite weekend of the year.
"It was a bit nerve-wracking at the beginning, but you get used to it," he says.
"The atmosphere is just lovely - and that gets you through the fact that you're playing music to 100,000 people. "