The upcoming Arrowverse crossover "Crisis on Infinite Earths" promises to be quite the delight for DC fans. Already, we know Tom Welling and Erica Durance will reprise their Smallville roles as Clark Kent and Lois Lane, respectively. Plus, it was previously confirmed that Batman voice actor Kevin Conroy will put in an appearance as an older Bruce Wayne -- and that's not all.Burt Ward will appear in an undisclosed role; Brandon Routh will once again suit up as Superman; a new Atom is coming to the screen; Birds of Prey's Ashley Scott will return as Huntress; and Lynda Carter might return as Wonder Woman. While all of these returning actors/characters would be more than enough for the event, it turns out that's not all.RELATED: Superman Dark: Routh Shares an Ominous Crisis on Infinite Earths PhotoIn fact, "Crisis On Infinite Earths" executive producer Marc Guggenheim has revealed there are more surprises left in store for the highly anticipated crossover.On Twitter, a fan asked Guggenheim if anymore "Crisis" news is coming. "Left to my own devices, there wouldn't be any more news breaks," the producer answered. "I want there to be a few surprises left. That said, it's not up to me..."

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Therefore, despite all the major reveals about the upcoming Arrowverse crossover so far, more are coming -- and fans may even find out about them before the event's December air date.

"Crisis on Infinite Earths" begins Sunday, December 8 at 8 pm ET/PT on Supergirl, then continues in Batwoman on Monday, December 8 at 8 pm ET/PT and in The Flash on Tuesday, December 10 at 8 pm ET/PT. After the winter hiatus, the crossover will conclude on Tuesday, January 14 in Arrow at 8 pm ET/PT and in DC's Legends of Tomorrow at 9 pm ET/PT.