Danielle Panabaker said that filming the highly anticipated crossover event between “Arrow,” “The Flash,” “Supergirl” and “Legends of Tomorrow” was like a family reunion.

In an interview with “The Lowdown with Diana Madison,” Panabaker opened up about what it was like to shoot the weeklong mash-up event with a lot of stars from different DC TV shows on The CW.

“At this point, it all sort of feels an extended family,” the 29-year-old actress said when asked what went down on set with several actors filming together. “We all have crossed paths basically in one point or another. So many of the ‘Legends’ characters originated on ‘Flash.’ I’ve been on ‘Arrow’ a handful of time. So it’s a lot of hugs in the beginning of the day. It’s great to see people and great to catch up.”

Panabaker, who plays Caitlin / Killer Frost on CW’s DC TV universe, added that there’s also a big difference in terms of logistics when shooting crossover episodes.

“It’s a lot of logistics,” she said. “Normally, we have two, three cameras, [but] then [for the crossover] we have five or six cameras trying to … cover … everyone.”

As for when fans can expect the crossover, Panabaker said: “It's ‘Flash’ episode 8. It’s ‘Arrow’ episode 8. It’s ‘Legends’ episode 7. So I think it airs at the beginning of December.”

“Arrow” and “Legends of Tomorrow” executive producer Marc Guggenheim revealed last month that CW’s DC TV heroes will all team up to defeat the alien race Dominators in the crossover.

“This year, for our mega ‘Arrowverse’ crossover, we’re taking inspiration from a DC crossover from the late 1980s known as ‘Invasion!’ which featured … the Dominators, who’d previously, vexed the Legion of Superheroes,” he said (via Entertainment Weekly).

In DC lore, the Dominators strongly believe that the unpredictable evolutionary tendencies of metahumans on Earth pose a dangerous threat to the state of the universe, so they work with other alien races to eliminate Earth’s metahumans.

Guggenheim told Superhero Insider that their version of Dominators have a very similar mission in the crossover. “I will say that their goal is very closely related to what was established in the comics, and it does have to do with metahumans,” Guggenheim said.  “It’s very, very faithful to the comics.”

Are you excited for the four-way crossover? Sound off in the comments below!

Danielle Panabaker as Caitlin Danielle Panabaker opened up about what it was like to shoot the much anticipated crossover event between “Arrow,” “The Flash,” “Supergirl” and “Legends of Tomorrow.” Photo: The CW