Actor Meaghan Rath is set to join Supergirl as a new Brainiac-5. Jesse Rath, Meaghan's brother who currently plays Brainiac-5 on the show, made the announcement during the Supergirl panel at Comic-Con International in San Diego today.
"[This is] something that I've been pitching since I got the role," said Jesse Rath. "You can't talk about Brainy without talking about his family. My real-life sister will be joining the show, Meaghan Rath. She will be playing a female Brainiac-5."
While Brainiac-5 has traditionally been portrayed as a male character, Meaghan will portray a female Brainiac-5 in the upcoming Season 5 of the Arrowverse series.
Meaghan is most famous for her lead role on Being Human, a Canadian adaptation of the British horror-comedy which ran from 2011 to 2014.
Jesse's Brainiac-5 joined the show as a member of the Legion of Super-Heroes in Season Three before joining the series' main cast in Season Four.
Unlike his villainous ancestor, Brainiac-5 has almost always been portrayed as a hero, either in the future of the Legion or the present day, since he was created by Jerry Siegel and Jim Mooney.
While it's not clear how many episodes Meaghan's Brainiac-5 will appear in, she'll join Jon Cryer, who's returning as the iconic villain Lex Luthor, and Tyler Hoechlin who will reprise his role as Superman for the Crisis on Infinite Earths crossover.
Returning Sunday, October 9 at 9 p.m. ET/PT on The CW, Supergirl stars Melissa Benoist as Kara Danvers, David Harewood as Martian Manhunter, Mehcad Brooks as Jimmy Olsen and Chyler Leigh as Alex Danvers.