Bad news for fans of Regina's (Lana Parrilla) happiness ahead of the fifth season of ABC's Once Upon a Time.

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Once Upon a Time fans will recall that Regina's sister Zelena (Rebecca Mader) was pregnant with Robin Hood's (Sean Maguire) baby in the final episodes of season 4. Well as it turns out, Zelena will be having that baby in the fifth season.

This news comes from Entertainment Weekly, who got to speak with OUAT co-creator Edward Kitsis ahead of San Diego Comic-Con.

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The pregnancy happened after Zelena killed Robin's wife Marion (Christie Laing) and subsequently disguised herself as her. Robin then impregnated who he assumed to be his wife and the rest is history.

It remains to be seen how this will affect Regina (and Robin), though Mader and Maguire have been promoted to series regular status for season 5, so the storyline is probably far from over.

In the mean time, Mader, Maguire and Parrilla will all be at Comic-Con along with their costars Jennifer Morrison (who plays Emma), Ginnifer Goodwin (Snow), Josh Dallas (Charming), Emilie de Ravin (Belle), Colin O'Donoghue (Hook) and Robert Carlyle (Rumple). Kitsis will also be at the fan event alongside his fellow co-creator Adam Horowitz. The panel, which takes place Saturday, July 11, will be moderated by actress Yvette Nicole Brown.

Once Upon a Time season 5 is set to premiere Sunday, Sept. 27 at 8 p.m. ET/PT on ABC.