Ad doesn't say any more, but that could point to Lewis Capaldi, who struggled to finish his set in 2023 before announcing a break from touring to get his "mental and physical health in order". He made a tentative comeback last month, and would be a popular choice.

Lana Del Rey also has unfinished business - her 2023 set was cut short after she breached the curfew. She's back on tour in the UK, with free days on the Friday and Sunday of Glastonbury weekend.

Other stars who have been rumoured include Lady Gaga, who hasn't played Glastonbury since 2009.

Asked earlier this year what it would take for her to return to the festival, she replied: "Not much". Gaga has already played Coachella and been on tour this year.

Lorde isn't on the bill either, but told BBC Radio 2's Jo Whiley this week she's "pretty keen" to be.

"The album's gonna be coming out right around that time," she said. "I am quite tempted by what's going on because I've got lots of friends playing as well. We'll see if I can pull some strings and get there."

The Secretglasto team have gathered and posted information about secret sets for more than a decade, and interest in their tips has gone "a bit crazy" in recent years.

Ad - who doesn't want to give his full name - says they have built up a network of reliable sources. "We've got loads of contacts at different stages and record labels and whatever else. And people trust us to be sensible with the information," he says.

"And the bands themselves don't want empty secret sets do they? So we have had occasions where they have come to us."

The six people who work on the account aren't music industry insiders themselves. Another team member, JB, says they sometimes approach acts directly to seek confirmation.

"Now that we've been around for 10 years and have a decent bit of clout, we will contact some of the artists via their inboxes, and quite often they're happy to confirm.

"Sometimes they don't. Sometimes they block us. But generally we're able to piece all that together fairly quickly."

He adds: "By the time the gates open, there aren't many things we don't know."

In the past couple of years, some acts have begun harnessing the buzz about secret sets for PR purposes for their album or tour, Ad believes.

"It used to just be friends of the festival, whereas now people are like, 'If we do the secret set we're going to get loads of hype and media attention'."

Ad was among the lucky few to see Lady Gaga play an after-hours set in Club Dada following her main appearance as her career was taking off in 2009.

"She did three or four hits and then disappeared," he recalls.

"Because the phone signal was so bad, you couldn't ring or text your mate to let them know. So only the people who happened to be there got to experience it, which was a few hundred.

"I'm surprised she hasn't come back. Yet."

That was one of the more exclusive secret sets in Glastonbury history. Others draw huge crowds when the word gets out - which it usually does.

Rogers was in the right place when she a rumour swept the site that Radiohead would play in 2011.

"We were over that side of the festival anyway, so on a wing and a prayer, just in case it was true, we dashed over to the Park Stage in good time, and we got pretty close to the stage," she says.

"There are reports that it was the biggest crowd on the Park Stage for a secret set ever. I'd waited my whole life to see Radiohead live, and then suddenly here we are, and they did this amazing set.

"As my first ever time seeing them, and being in prime position, and it being a genuine surprise - it was just pure glee. I was just so happy, and I couldn't believe it."

Secret sets have been a feature of the festival for decades.

In 1992, the line-up poster wasn't topped by a star name but the promise of "a special guest that we can't announce". That turned out to be Welsh pop stallion Tom Jones.

But Glastonbury's greatest ever secret set didn't happen at the festival at all.

In 1995, indie gods The Stone Roses pulled out of headlining after guitarist John Squire broke his collarbone.

But by the time organiser Michael Eavis threw his annual low-key autumn gig in the local village to thank residents for putting up with the main event, Squire was back in action.

So the band played their first UK gig for five years in a marquee on a Somerset playing field to a couple of thousand lucky people.

They still haven't appeared at the festival itself, however.

Unfinished business? Tick. Emotional return? Tick! Could Patchwork in fact be The Stone Roses making a long-awaited and triumphant appearance?

Who cares if the likelihood rating is -100/10. Add them to the list!