ABC brings the fairytale to television as "Once Upon A Time" Season 5 starts on March 6. The mid season reportedly reveals that it will focus on backstory of stepsisters, Zelena and Regina.

According to Carter Matt, episode 19 which is dubbed as "Sisters" will show the West Regina's childhood experiences of stepsisters, Evil Queen Zelena and the Wicked Witch. And younger actresses are needed to portray these two characters.

English actress Isabella Blake-Thomas, who is credited for her appearance on BBC's "The Green Balloon Club," will play as the young Zelena, according to TV Line. On the other hand, the site has reported that Ava Acres, who were known for the roles of young Rebecca in "Crazy Ex-Girlfriend" series and Melinda May in "Agents of S.H.I.E.L.D." had been casted in Episode 19 as young Regina. 

Fans will see the two characters in the long awaited episode as they were about to hit puberty. Regina, who was 10-years-old that time, will be "neglected and lonely," hence not showing enthusiasm on her mother's royal duties. Meanwhile, 12-year-old Zelena will discover her super powers but his father will strongly oppose.

Despite their past report that Zelena "was banished back to Oz in the midseason finale," she will return to Season 5B to have a head-to-head battle with warrior-mode Dorothy Gale. "[Zelena] is absolutely not done," co-creator Eddy Kitsis previously revealed on the website. "The Zelena story in Oz, with Dorothy, will tie into our Underworld story pretty significantly," he added.

"Once Upon A Time" will air on small screens this March 6, at 8 PM on ABC.