Singer Chris Martin has described a track written for Coldplay's next album as "basically genius", saying it could be their best composition yet.
Their next album will be Coldplay's fourth full-length studio release
The 30-year-old added that everybody "has to hear this song before we die, otherwise we'll be terribly depressed".
He said the band planned to return to the studio and would create a different sound to that of their last album, X&Y.
Their enduring success meant that they could experiment with "new things", he told a press conference in Mexico City.
"I think for a long time, people felt like we were a band in black-and-white.
"Because we have this incredible job, now we can do whatever we like, and try all kinds of new things," Martin added.
The group were in Mexico to conclude their Latin American tour, which had also seen them playing in Chile, Argentina and Brazil.