It looks like Coldplay's new album has a release date, if the stealthy detective work of fans is anything to go by.

The follow-up to 2014's 'Ghost Stories' has been rumoured for a release this side of Christmas, although there hasn't been any official announcement.

However, eagle-eyed fans spotted a mysterious poster in the London Underground yesterday, which had a geometric design that was the same as one that Chris Martin wore on stage at a gig last month.

Putting two and two together, it looks like the new album - allegedly called 'A Head Full of Dreams' - will be released on December 4th.

Coldplay played a new song 'Amazing Day' in New York last month - and you can see the design on Martin's t-shirt in the video below: