Giancarlo Esposito, Lana Parrilla Giancarlo Esposito, Lana Parrilla

Mirror, Mirror on the wall, who's the Evil Queen's true love after all?

Once Upon a Time's soulless, heart-crushing Evil Queen (Lana Parrilla) once had a love of her own — and it wasn't King Leopold (Richard Schiff), Snow White's father who will be introduced on this week's episode of the ABC drama. To find out who that love could be, turned to the Queen's right-hand man Sidney (Breaking Bad's Giancarlo Esposito), who also dishes on which fairy tale character the Mirror was before he was in the employ of the Queen.

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Based on the promos for this week's episode, Sidney will be trying to help Emma (Jennifer Morrison) take down Regina.
One of the wild cards in the story is Sidney. We don't quite know where he stands. Is he a good guy? Is he a bad guy? In this particular episode, you see he takes a stand against the mayor, which is very interesting because she's put him in his job. There is that mystical back story that we have in the fairy tale land that, oftentimes, relates to what we do in the Storybrooke world. This is an interesting episode because it leads to us finding out more about who Sidney really is in both worlds.

If he's turning to Emma, Regina must've really hurt him.
As you know, she is totally in control of everything in the Storybrooke world, or at least wants to be. She has really hurt his sensibilities. Sidney is really a guy who has some integrity. He is so wrapped up in the newspaper and wants to be able to tell the truth. This whole storyline is so much about the truth, and she really takes him down. Regina hurts his feelings in such a deep way, but it comes from that other world that we don't yet know about. You'll also find a very big surprise in this episode because all that you see is not really what's real.

Executive producer Adam Horowitz previously said that we'll see who Sidney was before he even became the Mirror. What kind of person was he before then?
He was a person who really believed in love and had aspirations and dreams. Because of what happened between he and Regina, that was taken away from him. Now, he's left with bitterness, anger and a desire to change his circumstance. Before that, he was a man that had hope and believed in people and goodness. So we see someone who is broken in many ways trying to find their way back to good.

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Lana Parrilla teased that the Evil Queen had a prior love interest in a character we have already met. With you saying something happened between the pair, is it possible he was her lover?
Absolutely. I would suggest that there was something a lot deeper between them that didn't go quite the way it was supposed to. Nothing is ever as it seems. We're assuming that it went both ways, but maybe it didn't. Maybe it was just another ruse. It is heartbreaking.

Will we recognize whichever fairy tale character Sidney was before he was the Mirror?
Oh, I think you will. It's such an interesting transition for this character. He's been enslaved in a different way and he becomes free only to be enslaved in this new way.

What will we see of their back story that helped to create the Evil Queen?
It will show how Regina is capable of many things. She's capable of incredible evil. She masks that out of the pain of her own loss, yet she uses that to propel her into a position of power. You'll really begin to see that this Regina, our Evil Queen, is a master manipulator.

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How will Sidney help to break the curse?
I don't know that he will yet. Everyone is just struggling to break the curse because they're stuck in the world of Storybrooke and don't know why. Deep down inside them, they yearn to know and want their freedom. I think all the characters, true to the show, will have the opportunity to experience a brief knowledge or wisp of the past which gives them the desire to get out. I think Sidney will help in many ways because he's so important to the community in writing the paper, so there's ultimately great opportunities for him to be the Paul Revere.

Which character do you think Sidney was before he became the Mirror?

Check out a sneak peek of Once Upon a Time, airing Sunday at 8/7c on ABC: