The songwriter formed the band with Keane bassist/percussionist Jesse Quin. The pair have been joined by a supporting cast of friends on their upcoming self-titled debut album.
Speaking to DS about the group, Rice-Oxley said: "It started off as a slightly drunken idea to try and make a classic country album, which seemed a bit ridiculous for two pasty English guys.
"From there it grew into something we're actually proud of and started to take much more seriously as a collection of songs... We wanted to make a record in a slightly different way and without the pressure of it being a Keane record."
Asked about the album's guest stars, who include members of The Killers, Mumford & Sons and Noah & The Whale, Rice-Oxley explained: "They're all people that either I knew or Jesse knew or both, and that we were friends with.
"They all brought different things - all of those people really added a flavour to the record which really made it much more than we could ever have made it on our own."
On how the project might affect Keane on their return, Rice-Oxley said: "I've definitely learned a lot from it, particularly in terms of my own writing.
"I always worked hard on my own songwriting, but I find the pressure of writing songs for Keane sometimes makes it hard to write instinctively - even though I try to - if that makes sense!
"I probably wrote much more instinctively and without really thinking about it, the songs became really true representation of myself and the things I was feeling. I really would love to try and access the same instinctive writing when it comes to Keane."
Mt. Desolation is released on October 18. The band are on tour now.