While assembling the various cameos and guest stars for the epic Arrowverse crossover event "Crisis on Infinite Earths" was a massive undertaking, one of the trickier additions was current DCTV star Black Lightning.

The crossover's showrunner and executive producer Marc Guggenheim noted that the inclusion of Cress Williams' Black Lightning was a particularly challenging one due to the actor having to fly back and forth from Atlanta—the primary filming location for Black Lightning—to Vancouver, where "Crisis" was filmed. To make things even more difficult, logistically, Williams' costume, specially modified to give off a pulsating electric aura, was expensive to transport between the two filming locations to accommodate Williams' series and the crossover.

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"His costume is a very involved piece of equipment that has to be traveled [and] has a separate handler that has to travel with it," explained Guggenheim in an interview with Variety. "It was suggested to me at one point, by one of the money people, ‘Does Black Lightning really have to wear his costume in the crossover?’ He has to wear that costume. It just wouldn’t be the same if he didn’t.”

For Guggenheim, it was important that Black Lightning appear in the crossover for more than a glorified cameo, with Williams flying between the two filming locations on the weekends to maximize his availability while Black Lightning's writing staff reduced his role in several episodes to better accommodate his involvement.

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