The upcoming fourth season of ABC's Once Upon a Time will be a big one for Regina (Lana Parrilla) as she deals with the loss of her true love and tries to move on.

ABC Previews 'Awake, Arise Or Be Forever Frozen' for Season 4 of Once Upon a Time

Fans of Regina were just as mortified as her when Emma (Jennifer Morrison) brought Robin Hood's (Sean Maguire) love interest Maid Marian (Christie Laing) back from the past in the Season 3 finale. Despite Regina's feelings for Robin Hood, fans should not be quick to assume that she will become embroiled in a "love triangle" plot.

"Who says we're doing a love triangle?" series co-creator Adam Horowitz told TVLine when asked about the potential plot line. "Hopefully it becomes less about the relationship itself and more about Regina [and] open[s] the door to who she is and what she's going to become."

Hook Continues 'Very Complicated' Relationship With Emma When Once Upon a Time Returns

The report also revealed some more details about Belle's (Emilie de Ravin) mother, who will be making her Once Upon a Time debut in Season 4.

Belle's mother is reportedly a "a strong-willed, spirited woman" who is very confident in herself "even under the most trying circumstances." She will be introduced for the first time in a flashback during Episode 6 of the new season.

Meanwhile, the series is set to introduce a whole new slew of characters from the world of Disney's massively successful animated film Frozen.

Once Upon a Time Season 4 is set to premiere Sunday, Sept. 28 at 9 p.m. on ABC.

Watch a promo for the new season of Once Upon a Time here: