“Swifties everywhere are sharing their theories after Taylor Swift‘s close friend and frequent collaborator, Jack Antonoff, shared a photo from December 2023 of the singer in the studio with producer Sounwave, whose real name is Mark Anthony Spears.

On Sept. 18, Antonoff shared some candid snaps from recording sessions at Electric Lady Studios in New York City. While photos featuring Sabrina Carpenterand Paramore got people talking, it was the photo of Swift and Sounwave, dated Dec. 21, 2023, that really caused a buzz.

It’s safe to say that Swifties went wild speculating about what the photo might mean, with one fan commenting on Antonoff’s post saying, “i’m going to need to know what Taylor recorded on my bday (12/21) so I can make it my entire personality thanks.”

“Also this is so cryptic like what are you plotting,” questioned a different fan.

As the news spread online, fans on X quickly reacted to the tease, speculating on what music Swift could’ve been working on at the time. Sounwave previously worked with Swift on “London Boy” from her album Lover, as well as “Lavender Haze,” “Karma” and “Glitch” from Midnights.

He didn’t appear to collaborate with Swift on any of her The Tortured Poets Department tracks, leading Swifties to hypothesize that the photo was taken while working on Swift’s next studio album, referred to as “TS12,” or one of her last two albums to be re-recorded, with many assuming that Reputation (Taylor’s Version) will be next.

“since sounwave didn’t work on ttpd, and the date says december…. she’s never not working omg dare i say this is ts12,” wrote one fan, as another wondered, “Guys this is probably TS12, rep TV was already finished last year, since she stated on her TIME’s interview that the rep vault tracks were ‘fire.'”

Some fans burst the bubble of excitement when they pointed out that Sounwave posted the same photo back in February while celebrating Midnights‘ success at the Grammys, although, with Midnights released in Oct. 2022, its unlikely that the photo originated with those recording sessions, unless the timestamp was altered for some reason.

When Sounwave posted it, the photo didn’t feature any date at the time, suggesting either Antonoff added the date or Sounwave removed it and indicating that there’s likely some significance.

Swifties will just have to wait and see if Swift has any surprises up her sleeve soon.