This spring, two of the CW's DC shows will stage a crossover unlike any other fans have seen before. The event will turn "Flash" and "Supergirl" into a full-blown musical, a move that makes sense considering that both series leads (Melissa Benoist and Grant Gustin) are "Glee" alums. And on top of that, Broadway vets Jesse L. Martin, Jeremy Jordan and Carlos Valdes are also amongst the shows' supporting casts.

There's another Broadway icon in the CW's DC universe, "Legends of Tomorrow's" Victor Garber, although whether or not he'll appear in the musical crossover remains unknown since he's not on "Flash" or "Supergirl." But executive producer Greg Berlanti is well aware of Garber's talents, and he seems to know that he can't do a musical superhero episode without him.

"Oh, I'd be crazy not to," Berlanti told ComicBook.com when asked if Garber's Martin Stein would be involved in the musical crossover. "He's got one of the best voices. He actually sang for me at an event once, and if I ever get married, I'd have him sing at the wedding."

Audiences have already heard Martin Stein's pipes in a recent episode of "Legends of Tomorrow." Earlier this season, Garber's character posed as Hitler's favorite singer in order to sneak the Legends crew into a Nazi bar for a mission. That scene culminated with Garber singing "Edelweiss" and a bar fight.

Garber also previously co-starred in Berlanti's "Eli Stone," a series where the titular lawyer's brain tumor caused him to hallucinate musical numbers.

It would make sense for the musical crossover to go for broke and get the "Legends of Tomorrow" star into the mix. When this crossover was announced, "Supergirl" EP Sarah Schechter said they have to do this event or they would regret it. “We’ve got such talented actors, 15 years from now when the last of these shows is going off the air, that would be a big regret [if we didn’t do it] -- it’s too much fun not to.”

While not much is known about the musical event, it has been stated that it will include already existing songs as well as a few new ones.

“Next week we’ll have to start talking about clearing music,” Executive Producer Greg Berlanti said in September. “I have a few ideas for tone and style in my head but we’re just starting to talk about what that can be. I do want to try and get an original piece of music written. As we make a deal on that we’ll probably make some announcements on the original songs.”

Airing Thursdays at 8 pm ET/PT on The CW, "DC's Legends of Tomorrow" stars Arthur Darvill as Rip Hunter, Brandon Routh as the Atom, Victor Garber and Franz Drameh as Firestorm, Caity Lotz as White Canary, Maisie Richardson-Seller as Vixen, Dominic Purcell as Heatwave and Nick Zano as Citizen Steel.