American Idol Katy Perry teases her 'Dear Evan Hansen' cover of 'Waving Through a Window' 11/03/2018 Katy Perry posted on Instagram Thursday a preview of herself singing "Waving Through a Window" from hit Broadway play "Dear Evan Hansen." Read More RELATED NEWS 'American Idol' couple Gabby Barrett and Cade Foehner expecting their first childKaty Perry honors late friend and mentor: "I am incredibly grateful"Bobby Bones joins 'American Idol' as in-house mentor for Season 17 TAGS: Katy Perry
