There was a big moment during Sunday night's episode of ABC's Once Upon a Time, with Lily's true identity being revealed.

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Lily was shown to be the child of Maleficent (Kristin Bauer van Straten), who was cursed with darkness before she was even born. This was Snow (Ginnifer Goodwin) and Charming's (Josh Dallas) doing, since they wanted to remove all the darkness from baby Emma, transferring it to Lily.

Once Upon a Time co-creators Edward Kitsis and Adam Horowitz spoke about this storyline in a new interview with Entertainment Weekly.

Snow & Charming Make 'A Terrible Mistake' on 'Once Upon a Time'

"When we met Lily, she didn't seem like a bad person, but she was lying to Emma," Kitsis noted. "Lying came second nature to her. What we're going to see is: We're all faced with choices and it's the choices you make. What happened to Lily and how she grew up is something we're going to really explore."

This will likely be explored further in the 19th episode of the season, which is appropriately titled Lily.

Kitsis and Horowitz spoke of how Snow and Charming may fully be redeemed of what they did as long as they return Lily to Maleficent.

"Sometimes you can change the past by changing the present," Kitsis explained. "They thought they killed the baby and now we realize Lily is out there, so the next step is someone has to reunite that child with Maleficent. Does that erase what they did in the past? No."

"We're talking about redemption, not time travel," Horowitz quipped.

It remains to be seen if Maleficent will truly find her happy ending in the form of Lily.

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

Watch the promo for the next episode of Once Upon a Time here:

Tags: Once Upon A Time television ABC