When Supergirl flashes back to Kara and Alex's childhood in Season 3 Episode 6, they'll look a little different. TVLine reports that the younger versions of the characters, formerly played by Malina Weissman and Jordan Mazarati respectively, have been recast.

The Americans star Olivia Nikkanen will take over the role of young Alex from Mazarati, while The Fosters' Izabela Vidovic fills the role of young Kara in place of Weissman. Nikkanen has previously appeared in Boardwalk EmpirePerson of InterestElementary and The Good Wife. Vidovic's past credits include About a BoyZombielandThe 100Bones and Halo: The Fall of Reach. She will also appear in Wonder.

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The two Supergirl newcomers will debut in Season 3's sixth episode, which is titled "Midvale." In "Midvale," Kara and Alex will take a road trip to their former hometown, “where they relive a murder mystery from high school that shaped their relationship as we know it.” In the flashbacks, both Kara and Alex will be in high school.

Returning to The CW on Monday, October 9th at 8 p.m. ET/PT, Supergirl stars Melissa Benoist as the Girl of Steel, David Harewood as Martian Manhunter, Mehcad Brooks as Jimmy Olsen, Chyler Leigh as Alex Danvers and Jeremy Jordan as Winn Schott, with appearances by Calista Flockhart as Cat Grant and Tyler Hoechlin as Superman.