The 'Get Better' hitmaker gushed about the American rock god and record producer who he worked with on his new LP 'Positive Songs for Negative People' and wishes he'd been friends with him ''a long time ago''.
Asked what it was like working with the 45-year-old rocker, Frank said: ''Amazing. He's my spirit animal. Part of me wishes we'd met a long time ago. He's a great producer, songwriter, all-round lovely chap. He really helped me and the Sleeping Souls get the vibe right on this album. He pulled the best performances out of us.''
The folk rocker who is releasing his sixth studio album - since his band Million Dead retired - went to Nashville, Tennesee specifically to work with Butch and not to ''soak up the atmosphere''.
He told The Sun newspaper: ''I wanted to work with Butch Walker, and that's where his studio is. We didn't really soak up the country atmosphere or anything.''
Meanwhile, the 33-year-old musician admitted he gets ''bored'' quickly and that allowed him to go ''harder and faster'' writing lyrics so he wasn't ''complacent''.
He added: ''I get bored easily, haha. Actually I made a conscious effort with this record to go harder and faster with my song writing. I didn't want to sound, or indeed be, complacent in any way.''