Behind the Scenes of the Arrowverse Crossover 'Crisis on Infinite Earths' (PHOTOS)

"The Flash makes a great Jonah Hex," Johnathon Schaech wrote in a caption of Grant Gustin's character wearing Hex's hat.

"The Monitor out here cheating.... A Crisis is Coming," LaMonica Garrett (The Monitor and Anti-Monitor) wrote in the caption of this photo.

"Crisis On Infinite Earths is going great!" Stephen Amell wrote in the caption of this photo of himself looking very bloody and bruised.

"Pink glasses, pink hair clip, pink lips," Erica Durance wrote in the caption of a photo from set. "Getting ready to Rock as Lois..."

"Brave leaders answering their personal calls to COURAGE!" Schaech wrote in the caption of a photo of himself with Gustin, Matt Ryan, Caity Lotz, and Katherine McNamara from the crossover set.

"So, I was just minding my own business, and I ran into this guy," Durance wrote in the caption of a photo of her and Tom Welling in a familiar place. "Laughed until I cried! So much fun."

"Lois and Clarks," Elizabeth Tulloch wrote in a caption of a photo with both Smallville and the Arrowverse's Clark Kents, Welling and Tyler Hoechlin.

"Look who I found during a recent visit to the #DailyPlanet," Brandon Routh wrote alongside of a photo of him getting back into his previous role on October 3.

"#DoubleVision—the new #Superman ability!" Routh wrote in the caption of a photo of himself and Hoechlin dressed in their characters' super-suits on October 1. "Grateful to share the #Arrowverse as #Superman for a short time with the charming & gracious @tylerhoechlin! I never really thought I'd get to meet #Superman in person... Gotta say, it's all it's cracked up to be!"

"Game recognizes game and powers recognizes powers," Williams wrote in the caption for the photo of him on set for the crossover on October 8. "#grantgustin is a true pro and a great new friend."

David Ramsey shared this behind-the-scenes photo of himself, Amell, McNamara, and Ryan on October 10.

"#SuperFrinds," Routh captioned this photo with Hoechlin and Grant Gustin in their suits on October 9.

"I love playing in other people’s sandboxes," Cress Williams wrote in the caption of this photo of his chair on the set of DC's Legends of Tomorrow for the crossover on October 11. "Having a blast."

Williams also shared this welcome message from The Flash for his work on the crossover on October 8. "Playing with some great new super friends," he wrote in the caption.

Both Lois Lanes in the crossover shared this photo on Instagram on October 8.

"The New Adventures of Lois and Lois," Tulloch wrote.

"Had so much fun with this Gal last week," Durance said. "What a badass."

Tulloch posted this photo as a TBT on October 3 to the first day of filming for the crossover the week before. "This crossover schedule has been bananas but the final product is going to be epic," she wrote.

"About today...," Amell wrote on October 16 with his photo featuring him and his daughter alongside Melissa Benoist, Grant Gustin, Ruby Rose, Tyler Hoechlin, Brandon Routh, and someone whose identity has been hidden.

"Still not over this," Osric Chau, who's joining the Arrowverse as Ryan Choi, wrote alongside a photo of himself in front of his trailer on October 16. "Having the best time on sets!"

"Traveled back in time on my birthday (yesterday) to a time before #RayPalmer knew #TimeTravel existed," Routh wrote alongside these photos from the Palmer Tech set on October 10.

Williams shared a video from the set of DC's Legends of Tomorrow's Waverider on October 8. "Sometimes you gotta take the controls," he wrote in the caption.