Another key Little Mermaid character is heading to ABC’s Once Upon a Time. Ernie Hudson has been cast as King Poseidon in episode 15 of the fairytale drama’s current fourth season. In a twist, in addition to being the the powerful deity of legend, in the Once Upon a Time world, we will also discover that Poseidon is the father of the villainous Ursula, played by Merrin Dungey. The two will be joined by JoAnna Garcia Swisher, who will be reprising her role as Ariel.
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