Iggy Pop and Josh Homme were inspired to make music from their shared interests in "[their] sex life, furniture and German trivia".
The rockers - who teamed up with Arctic Monkeys' Matt Helders for the secret LP titled 'Post Pop Depression' -had a bizarre bonding session where they talked about their ideas for the album.
On working together, Iggy told Matt Wilkinson in a forthcoming Beats 1 Radio interview: "About half way through, we had a conversation about what we wanted to do. We didn't want to take anyone's money, we didn't want a record [label] person up our ass - we were willing to use our own funds."
Josh added: "It was a diverse layout of interests."
And Iggy revealed the things that turned them both on were, "Sex life, furniture and German trivia".
Meanwhile, the 68-year-old rocker said the band - which also includes Dean Fertita, from Queens of the Stone Age, and the Dead Weather, on guitars and keyboards - "sound really bloody good" live.
The record, which was made over a year ago between Josh's two studios in Los Angeles, Joshua Tree and Pink Duck in Los Angeles, is expected to be released in March.