In an interview with NME, Pete Wentz said he thought about the shift in terms of how he thought about bands like The Clash.
"At the time The Clash did so many departures and I was like 'what the f***? I just want this punk band'. But now, in retrospect I don't think that I would've liked The Clash as much if they hadn't made the change. It's like with Bowie and all these artists I've loved - they changed depending on the era.
"I think maybe in the moment it's harder to swallow, but even when I look at an artist with Kanye, I mean, could he have kept doing the soul samples with rap? Yeah, he could've. But I think he's more dynamic and interesting as an artist because he shows he can transform."
Fans will get to see what the new album holds when it releases in mid-September, and they'll get to see Fall Out Boy live next March when they return as part of their worldwide Mania tour.
Tickets go on sale next Thursday, July 20, via Ticketek and there's a pre-sale starting Monday via FallOutBoy.com.
LOWDOWN:
What: Fall Out Boy's Mania tour
When: March 7, 2018
Where: Trusts Arena, Waitakere