Supergirl enjoyed a ratings spike last season when Grant Gustin guest starred as The Flash, so it’s no surprise that another crossover is planned for this year. Less expected is the fact that this season’s two-episode crossover is going to be a musical.There have been other shows that have broken format to provide musical episodes, most famously Joss Whedon’s “Once More With Feeling,” a sixth season episode of Buffy The Vampire Slayer .

Among those breaking into song from The Flash will be Gustin and Jesse L. Martin, while the Supergirl side of things will include Melissa Benoist and Jeremy Jordan. While most of the songs will be pre-existing, there will be some originals written specifically for the shows.