After the full Glastonbury timetable was published this week, one bands name was on everybodys lips. Except no-one knows who they actually are.
Patchwork have a prime place on the festivals line-up - third from the top of the bill on the main Pyramid Stage on the Saturday night. The only thing is, theres no band called Patchwork.
Its a fake name for a mystery guest - just as an unknown band called The ChurnUps were on the Pyramid bill in 2023, and turned out to be the Foo Fighters.
Fans immediately went into overdrive to try to work out Patchworks identity - part of the frenzied guessing game surrounding the festivals "surprise" sets.
The main theories include:
In conclusion: I dont know.
"Radiohead also are in the mix of rumours because theyve been teasing some tour action," suggests music journalist and broadcaster Georgie Rogers, who was a judge for Glastonburys emerging talent competition this year and is DJing at the festival.
"Or could Elton John be returning to do something with Brandi Carlile?"
Sir Elton headlined in 2023, and Carlile, his collaborator on his last album, is on the Pyramid Stage bill on the same day as Patchwork.
The Patchwork slot is just one of several tantalising gaps in this years schedule.
Another mystery Pyramid performer is listed as "TBA" for Friday afternoon, while the smaller Park and Woodsies stages - which have hosted secret sets by big names in the past - each have an empty space on the line-up.
"Theyre quite prominent sets, and they do tend to put in massive artists," says Rogers.
One group of fans think they know who will fill those gaps.
"Of the four main slots, I think weve got three of them, maybe four, nailed down," says Ad, one of the people behind the Secretglasto social media account.
"I think its definitely people who have got relationships with the festival who will be doing the big slots. An emotional return for one or two, I think. Some unfinished business."
Ad doesnt 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. Shes 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 hasnt 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 isnt on the bill either, but told BBC Radio 2s Jo Whiley this week shes "pretty keen" to be.
"The albums gonna be coming out right around that time," she said. "I am quite tempted by whats going on because Ive got lots of friends playing as well. Well see if I can pull some strings and get there."
The Secretglasto team have gathered and posted information about surprise sets for more than a decade, and interest in their tips has gone "a bit crazy" in recent years.
Ad - who doesnt want to give his full name - says they have built up a network of reliable sources. "Weve 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 dont 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 arent music industry insiders themselves. Another team member, JB, says they sometimes approach acts directly to seek confirmation.
"Now that weve 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 theyre happy to confirm.
"Sometimes they dont. Sometimes they block us. But generally were able to piece all that together fairly quickly."
He adds: "By the time the gates open, there arent many things we dont 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 were 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 couldnt 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.
"Im surprised she hasnt 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 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. Id 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 couldnt believe it."
Secret sets have been a feature of the festival for decades.
In 1992, the line-up poster wasnt topped by a star name but the promise of "a special guest that we cant announce". That turned out to be Welsh pop stallion Tom Jones.
But Glastonburys greatest ever secret set didnt 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 made an unannounced live comeback after a five-year absence in a marquee on a Somerset playing field to a couple of thousand lucky people.
They still havent 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!