Spoilers for season 4 of "Once Upon a Time" revealed that the Wicked Witch will be coming back as Regina's search for the Author continues.

According to the report from TVLine, Rebecca Mader will reprise her role as Zelena, also known as the Wicked Wtich of the West.

"No details are available about Mader's return," the report said. "Except that she will appear in flashbacks at some point during the second half of Season 4."

Lana Perilla teased "Once Upon a Time" season 4 spoilers to Entertainment Weekly that her character Regina is still trying to find the Author's library.

"This is a quest that has been quite difficult for Regina," she said. "With all the research she's done thus far and Operation Mongoose, she keeps hitting dead end after dead end. She's lost some faith in ever finding this author, but she's still not going to give up."

However, she said that Henry has given his full support for his mother in her quest to find the author.

"A lot of that positive reinforcement comes from Henry in being the heart of the truest believer, who keeps her afloat and keeps encouraging her to not give up," Lana Parilla said. "He plays a huge part in finding clues. They work together and start to find clues leading to the discovery of this author, so that will play out for the remainder of the season."

Regina, however, has some competition as Mr. Gold is also trying to find the Author, and even plan to solicit the help of Cruella de Vil, Maleficent and Ursula to increase the chance of success. Mr. Gold wants the Author to change the way villains are depicted in Storybrooke.

Watch out for more "Once Upon a Time" Season 4 spoilers as the show returns on Sunday, March 1.