Regina's (Lana Parrilla) battle with her own self will begin when ABC premieres the sixth season of "Once Upon a Time" in September.

In the finale episode of season 5, Snow (Ginnifer Goodwin) advised Regina to use Jekyll's (Hank Harris) serum so she could finally get rid of her Evil Queen persona once and for all.

But while Regina managed to crush the Evil Queen's heart, it reanimated and launched a war against the good Regina by stealing the Dragon's heart. This means that Parrilla will have to play two big roles who will try to outlast each other in the upcoming season.

Speaking with Entertainment Weekly, executive producer Edward Kitsis revealed that the two opposite personas of Parrilla's character will shine in season 6.

"The two roles are obviously going to be very separate in the sense that we saw a snippet of an Evil Queen who looked at what Regina has become and is very disappointed," Kitsis said. "If she's unleashed, she would show Regina what ripping away everyone's happy ending truly looks like."

Co-executive producer Adam Horowitz also revealed that Regina might have trouble fighting for the other version of herself now that she has decided to remove the evil character from inside her.

"There's a lot of questions to be asked about what it means when you separate parts of yourself and can you really separate these parts of yourself?" Horowitz stated.

Meanwhile, Horowitz also revealed to the publication in a separate interview that The Land of Untold Stories arc in season 6 will become a venue for the fans to understand what exactly is going on with the Storybrooke characters next season.

"The intent is that these new characters and new stories are really a reflection on what's going on inside of our characters," the executive producer said. "With Lana and the Evil Queen, that's the starkest example, which we've already teased. We're literally going inside her and pulling her apart. There are elements of that that we're planning to do for each and everyone of the characters."

"Once Upon a Time" season 6 premieres on ABC on Sunday, Sept. 25.