Drop everything: The Flash and Supergirl are planning a two-part musical crossover on the CW. MUSICAL. CROSSOVER. The magical two-parter will air at some point during the back half of next year.

ICE CREAM FOR EVERYONE.

Executive producer Greg Berlanti made the announcement at the Television Critics Association panel on Thursday. He added that the musical crossover will feature preexisting songs — so former Glee stars Melissa Benoist (Supergirl) and Grant Gustin (The Flash) should feel right at home — but they're hoping to write at least one original song per episode. As for the premise, expect it to go down as some sort of dream sequence. (Or maybe the Music Meister will come out to play.)

"We've toyed with who potentially the villain could kind of be," Berlanti said. "My sense is we'll be very careful about how it is they kind of break into song and there will probably be an element of being in some character’s head at the time."

Fans have been clamoring for a musical episode in the Arrowverse since The Flash premiered in 2014. Perhaps you didn't know this yet, but the cast of The Flash consists of some extraordinarily talented musicians, including Jesse L. Martin (RENT), Carlos Valdes (Once the Musical), and Gustin (Glee). Supergirl also boasts some incredible musical talent; Benoist blew us away as Marley Rose in Glee, Jeremy Jordan starred in Newsies on Broadway as well as the movie musical The Last Five Years alongside Anna Kendrick, and Chyler Leigh has already done this musical episode thing on Grey's Anatomy.

Berlanti hasn't ruled out other members of the Arrowverse joining in on the musical fun. But don't expect Stephen Amell to be one of them. Arrow himself told MTV News back in June that if there were to ever be a musical crossover, he'd pass. "I'm out! I'm the first one," he said. "I get to draw the line, and I draw the line at musical."

Then again, judging from his latest tweet, it looks like Amell didn't even get an invite — so maybe he'll warm up to the idea out of pure FOMO.

Of course this crossover is different than the four-way crossover event happening in December with The Flash, Arrow, Supergirl, and Legends of Tomorrow. Since Supergirl exists in an entirely different world (the joy of the DC multiverse!), expect to see her pop up in the second part of that two-part event.

And if you weren't already sold on this monumental musical crossover, then perhaps MTV News can change your mind. Here's what happened when we asked the cast of Supergirl to create a song on the spot:

2017 literally cannot come soon enough.