So it's finally happened. Short of the Lighthouse Family getting Mick Hucknall in to perform a Chris Rea cover, the most middle-of-the-road Glastonbury moment in history is in prospect.
Muse frontman Matt Bellamy has told the Radio 1 Breakfast Show that, "The best thing for [Adele] to do would be to come the night before, watch us and come on and sing a song with us. That will take the pressure off, that will be a no pressure moment."
For a start, we have no idea how, musically, that would even work, but secondly, whatever happened to danger in music? Why would we want to take the pressure off Adele? The only really interesting part of her forthcoming Glastonbury performance is going to be whether she copes with a crowd far bigger than anything she's ever done before. Of course, she'll almost certainly do the business - she's never failed yet - but we at least want to see that leap in the dark don't we?
But then leaping in the dark is not a phrase that can really be used in connection with this year's Glastonbury.
The three headliners are, to be frank, pretty uninspired choices.
Coldplay will put on a magnificent show, but we've seen it all before. Fully three times before, in fact.
Muse, meanwhile, have topped the bill twice already and, again, while they put on a serious spectacle, musically they've been in decline over the last few albums. What's going to get the biggest cheer of the night? It's not going to be anything from Drones is it?
And Adele? Again, it's hard to argue with her as an artist, but she's not exactly tooled up with festival-rousing bangers (although a mass 'this-is-for-my-bastard-ex' shoutalong to the chorus Hello could be a pretty great moment), and she's already established as the biggest singer in the world already - she doesn't exactly need the exposure.
It's all incredibly safe, lacking the potential for a newer act to swashbuckle their way into the top league, someone to prove the haters wrong (Kanye, for all his faults, was a worthy - if you pardon the pun - booking) or for a legend of the game to quietly remind you why they're one of the greatest artists ever - just in case you'd forgotten.
Of course, every Glastonbury fan out there - myself included - will tell you that, obviously, there's about 3,000 other stages to pick from in the vast, wild plains of Worthy Farm and they're right, but due to the sheer size, scale and - inevitably - knee-deep mud blocking your way, you're hardly going to see any of them as it takes about an hour to get between stages. In addition, with sold-out, enormous crowds and poor walkway provision, if one drop of rain descends on Pilton (and even if it doesn't), you're going to be constantly battling against thousands of other people and dealing with constant bottlenecks.
Glastonbury is about much more than the headliners, but they matter - a lot of people are keen to stick around the Pyramid Stage for the day rather than move around, and many look forward to it as the big communal finale. They deserve a great headliner - and it also puts down a marker for the mentality of the festival.
With expensive tickets, that only people with organised buying strategies and super-charged WiFi can get hold of - aka middle class Guardian readers - and a wealth of excellent, smaller competing festivals out there, it's in serious danger of losing its edge (ironic, given that they've booked LCD Soundsystem).
Don't let Glastonbury turn into Coachella, where it's more about the selfies than watching any actual music. Don't let it get too middle class. Don't let it get too boring. Don't let it get too safe.
And let's start by asking Adele, politely, not to duet with Muse. And instead to do a duet on Shut Up with Stormzy instead. He'd definitely be up for it.