The band have previously hinted it could be their last, with Chris Martin describing it as "the completion of something".

The first single, an upbeat, summery track called Adventure Of A Lifetime premiered on BBC Radio 1 on Friday.

Speaking to breakfast show host Nick Grimshaw, the band dropped hints about a headline appearance at Glastonbury.

"We'd love to do it. That's our spiritual home, as a band," said Martin.    

"Maybe we should have called ahead and asked them," he joked.

All of Coldplay's previous albums have reached number one in the UK. Last year's intimate and melancholy Ghost Stories was the fourth best-selling record of 2014 worldwide, shifting 3.7 million copies in total.

The band went straight back into the studio after its release to record the follow-up, which Martin described as "a more colourful, more joyful sort of thing".

"It's the sound of us being free and happy and very grateful to be in our group."

Recorded in Los Angeles, Malibu and London, A Head Full of Dreams will feature guest appearances from Beyonce, Noel Gallagher and Tove Lo.

Martin said the record had been "handed in" three weeks ago, after the band set themselves a deadline of finishing it before the end of the year.

"It gradually moved later and later - but we came in relatively on time," he said.

"We'd still be working on it if somebody said we could be," joked drummer Will Champion.

The band are also planning to tour "early next year", after only playing a handful of low-key shows to promote Ghost Stories.

Speaking to the BBC last year, Martin suggested the new record could be Coldplay's swansong.

"It's our seventh thing, and the way we look at it, it's like the last Harry Potter book or something like that," he told Zane Lowe.

"Not to say that there might not be another thing one day, but this is the completion of something.

"I have to think of it as the final thing we're doing. Otherwise we wouldn't put everything into it."

Source: BBC