Casting announcements for CBS' Supergirl TV series - from Greg Berlanti (Arrow, The Flash) and Ali Adler (Glee, The New Normal) have made it evident fairly quickly that the show will be shying away from any of Kara Danvers/Zor-El's (Melissa Benoist) Kryptonian backstory. Beranti's past DC shows have been steeped in as much reality as possible given the content, so the addition of a show centered around a character like Kara leaves one to wonder just how mythological and out-there the creators are willing to take it.
The casting of Laura Benanti as Kara's biological mother, Alura Zor-El, led some out there to wonder if the series might incorporate flashbacks to Kara's time on Kyrpton before its destruction into the story - much like how Arrow is told through a half-present/half-flashback structure. That might well be the case, going by the latest casting update.
Filming on the Supergirl TV show pilot episode is currently underway, but THR is reporting the series has added Malina Weissman (Teenage Mutant Ninja Turtles) to the cast as a younger version of Benoist's Kara during her time on Krypton. She is set to guest-star in the pilot episode, but will most likely return for future installments of the series.
This won't be the first time Weissman will play a younger version of an iconic character; her role in the TMNT reboot was that of young April O'Neil (played by Megan Fox as an adult), and it looks like Weissman will be appearing via a flashback in the pilot. Whether or not this plot device will be as frequently used as on Arrow, however, remains to be seen, as nothing more on the subject is mentioned in the latest casting update.
Presumably, the flashback with young Kara will also include Benanti's Alura - allowing the Supergirl pilot a means to show Kara interacting and learning from her mother when she was younger. Which makes even more sense considering Alura's role in the show has been described as a, "strong noblewoman [whose] wisdom and guidance echoes across space and time." Much the same could be said for how Barry Allen (Grant Gustin) remembers his mother in The Flash.
It'll be interesting to see how Krypton is handled on Supergirl, given the series' available budget (all the more so compared to the planet's portrayal on the upcoming Syfy series Krypton). Arrow and The Flash have shown no signs of hesitation in going for large-scale sets and high amounts of visual effects in the past, so whether or not we'll see Kara's home planet as a society or limited to rooms, will probably only be confirmed when the series premieres.
Supergirl (assuming it gets picked up to series) will begin airing on CBS in Fall 2015.
Source: THR