The second half of season 4 of ABC's Once Upon a Time will features a big flashback episode that details Regina (Lana Parrilla) and Maleficent (Kristin Bauer van Straten) first meeting.

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Parrilla recently spoke with TVGuide.com about an upcoming episode of Once Upon a Time that features a flashback shared between Regina and Maleficent.

The actress said that they will share a "huge" flashback episode taking place before Maleficent was slain by Emma (Jennifer Morrison) when the former was a dragon.

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"Regina and Maleficent have a really interesting history," Parrilla teased. "You'll see how they met and how they became friends."

Maleficent is slated to return to Once Upon a Time during the next episode of Once Upon a Time, according to a new ABC press release.

The synopsis for the episode Heroes vs. Villains reveals that the three big villains set to star in the second half of the season will be guest starring in this episode. Van Straten's Maleficent, Victoria Smurfit (Cruella De Vil) and Merrin Dungey (Ursula) are all slated to guest star in this winter finale that airs this Sunday.

Maleficent and her fellow villainesses are the latest to terrorize the show's heroes after the Snow Queen (Elizabeth Mitchell), the Wicked Witch (Rebecca Mader) and Peter Pan (Robbie Kay) before them.

Once Upon a Time airs Sundays at 8 p.m. ET/PT on ABC.

Watch the promo for the winter finale of Once Upon a Time here:

Tags: Once Upon A Time television ABC