On their new album Wilder Mind, Mumford & Sons made the switch from arena-folk to firmly generic Coldplay-core rock. As it turns out, though, that isn’t the first musical transition they made. A new documentary reveals the band’s roots. All four members, we learn, were part of a circa-1998 boy band called Mumtown. Jimmy Kimmel, oddly enough, was also a member. And on his late-night show, Kimmel took a look back by airing a few minutes of that documentary. Watch it below.

Honestly, if “I Am My Heart” had been on Wilder Mind, it would’ve probably been the album’s best song.