Muse have released five studio albums and three live albums, after forming in 1994. A sixth studio album is understood to be currently in the process of being recorded, which is expected to be released in October.
The band’s multi-platinum-selling Black Holes and Revelations album earned the band a Mercury Prize nomination.
Chalmers declined to comment on whether the brief is expected to be a long-standing account, or will be for a short-term project alone.
Chalmers also handles the PR for Radiohead, Coldplay, Kate Bush, Robbie Williams, Kylie, Yoko Ono, Noel Gallagher and The Stone Roses.
Chalmers launched his own agency three years ago, after a 20-year stint at EMI, where he was PR director.