Harley Quinn writer and producer Patrick Schumacker has revealed Kaley Cuoco and sister Briana Cuoco influenced Harley and Batgirl's bond. The Big Bang Theory and The Flight Attendant star's younger sister joined the DC Comics animated series as Barbara Gordon in season 2. Harley Quinn season 3 debuted on HBO Max on July 28th, 2022.

Created by Gardner Fox and Carmine Infantino and originally making her comic debut in 1967, Barbara Gordon is the daughter of Commissioner Jim Gordon, who eventually takes up the identity of Batgirl and join Batman in his fight against crime. Voiced by Briana Cuoco, Barbara Gordon joined the cast of Harley Quinn in season 2, where she helped Harley (Kaley Cuoco) and Poison Ivy (Lake Bell) defeat the Riddler (Jim Rash) amidst the chaotic no-mans-land of Gotham City. Barbara is soon inspired by her experience to become Batgirl. With Batgirl featuring in season 3's trailer, the character's story is set to continue as Barbara works alongside her father and the rest of the Batfamily, and one of the series' producers has teased how Batgirl's bond with Harley was inspired by the cast.

Related: Harley Quinn Changes Batgirl's Origin Story

In an exclusive interview with Screen Rant during San Diego Comic-Con, writer and producer Schumacker offered insight on Batgirl's involvement with Harley in season 3, stating that the similarities between the Cuoco sisters helped influence the two characters' dynamics. Revealing that Harley and Barbara would establish a stronger bond as the season progressed, the writer explained that both characters would find a common ground and similarities between one another. Schumacker emphasized that the Cuoco sisters' relationship helped inform the sisterly bond that is explored between Harley and Barbara. Check out the writer's response below.

"They're so alike in their cadence and in their speech, that I think it works out. Especially this season in the show, where we start to see Harley and Batgirl become closer and find that commonality. I think it really underscores that theme, and that idea with those two characters that they are kind of sisterly - because they literally are."

Harley Quinn Season 3 Kaley Cuoco and Briana Cuoco as Harley Quinn and Batgirl

After Batgirl revealed her identity to her father Jim Gordon (Christopher Meloni) to save him from falling further into alcoholism and inspire him to better himself to protect Gotham City, season 3 is set to further explore how both characters protect the city. After being convinced by Two-Face (Andy Daly) to eventually run for Mayor when he manipulated him into capturing the villains attending Ivy and Kite-Man's (Matt Oberg) wedding in season 2's finale, season 3's red-band trailer teased that Gordon will run against the Joker (Alan Tudyk) when the sitting mayor is impaled by a steel pipe. Meanwhile, the trailer also saw Barbara continue to work alongside Batman and his allies Robin (Jacob Tremblay) and Nightwing (Harvey Guillén), as well as teaming up with Harley to take down henchmen, much to Barbara's reluctance at Harley's violence.

While Harley Quinn season 3 will further expand the series' cast, the show also promises to build on its core cast of Gotham City's most famous and infamous residents in their ongoing stories as Harley and Ivy navigate the next stage of their life together. As Barbara further grows as a hero, season 3's team-up between her and Harley is sure to explore how both have changed since their season 2 meeting. With Schumacker revealing that the Cuoco sisters' relationship played a part in Harley and Barbara's friendship, fans are sure to be curious to see how the animated series will explore the characters.

Next: Joker Weirdly Got His Perfect Revenge Against Harley Quinn