NEW YORK, NY - SEPTEMBER 26: Musician Chris Martin of Coldplay performs onstage at the 2015 Global Citizen Festival to end ex
Michael Kovac/FilmMagic

Coldplay's new album, tentatively titled A Head Full of Dreams, will drop on December 4... if fan theories are to be believed.

Although no official word has come from the band, Twitter users have noticed a mysterious poster in a London Underground train station featuring a rainbow "flower of life" pattern with the December date.

There's no mention of the British rockers, but eagle-eyed Coldplay supporters have noticed that frontman Chris Martin has been rocking the symbol on T-shirts lately, including a recent appearance at Global Citizen Festival:

Martin previously called the LP "the final thing" for the band, adding "it's like the last Harry Potter book or something like that." While he added the comment "Not to say that there might not be another thing one day," it sounded like the record could be Coldplay's last for a while.

The follow-up to 2014's Ghost Stories was rumored to drop before the year ended.