Passion Pit’s third studio album Kindred is out April 21. It’s been a long time coming: the band’s frontman, 27-year-old singer-songwriter Michael Angelakos, had to take a break from touring for his 2012 album Gossamer to focus on treatment for bipolar disorder, a condition he’s grappled with for nearly a decade. In conversation with TIME, Angelakos discussed how his new album shows how far he’ come with his recovery and his surprising dream collaborator. TIME: A few years ago, you said you wanted your next record to be about “real love” and be something “optimistic,” because you felt like you hadn’t written an optimistic song in more than a decade.