Taylor Swift: She'll be in the country over Glastonbury weekend, headlining British Summertime in Hyde Park. That's on Saturday, and then on Monday, she's heading to Dublin - which leaves a perfect, Glastonbury-sized gap on Sunday. It would be rude for her not to really.
Prince: It just wouldn't be Glastonbury if there wasn't wild speculation that Prince is planning a secret set. He never has, and probably never will. At this point, we'll almost be disappointed if it DOES happen (but still, PLEASE PRINCE - we want to see your purple wellies).
Noel Gallagher: We're not even going to waste all of our time suggesting that Oasis might perform a secret set, but Noel Gallagher and his High Flying Birds is a definite possibility. Discussing the fact that he hadn't been invited earlier this year, he admitted "I would do it though, if I was asked."
Radiohead: They've done it before, back in 2011, when Thom Yorke and Jonny Greenwood arrived unannounced on The Park stage and thousands flocked to it, forcing stagff to cut off access to the area as it reached capacity. If they did it again, it would no doubt cause just as much excitement - though maybe it's a little too soon.
Foals: There's a lot of hype around their truly huge new single 'What Went Down', and the rumour mill seems to be churning more strongly around Foals this year than any other act. They've got a host of European tour dates on the horizon, but nothing in the UK, so this would work out perfectly.
Fleetwood Mac: In a recent interview with The Sunday Times, Stevie Nicks sounded excessively exhausted: "Maybe I shouldnt be saying this in an interview, but I dont really care. I have done my best, every single night, to go out there and be my best, and not be upset about the fact that we are doing 80 shows instead of 60, and then going straight to Europe and doing 27 shows instead of 17." With that in mind, we actually hope they're not playing a secret set. Stevie needs a break.
Blur: They've just headlined Isle Of Wight Festival, and are in London this Saturday to play Hyde Park's British Summertime Festival, so - while they're on a roll - perhaps they could squeeze in a surprise appearance at Glastonbury too before heading off to Portugal, Spain, China and Australia next month.
Ride: They've just announced a set of UK tour dates to coincide with the 25th anniversary of their debut album, Nowhere. That tour doesn't kick off until October though, and so before that, Ride's name is being cautiously but optimistically attached to a possible secret set at Glastonbury.
Bastille: When a fan tweeted Dan Smith saying, "What's this I hear about you doing a scret gig @GlastoFest on Friday", Smith retweeted it. That's as close to confirmation as we're going to get, but if it's true, he's sort of ruined the surprise.
The Charlatans: If secret sets are supposed to a secret, then no one told Tim Burgess - who has been dropping some pretty massive and obvious hints on Twitter, including a picture of some wellies, the phrase 'special guessed yet?' and basically retweeting confirmation.