When someone asks you if you're a god, you say "yes."
The story notes that in the Once Upon a Time world, 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.
Hudson, who has also appeared in genre fare like Psych and Transformers Prime, recently appeared on the fan-favorite legal drama Franklin & Bash, which aired its final episode in October.
Update: To clarify, when the original source linked above reported the casting, they included mention of the Little Mermaid and an image of King Triton (which we also initially included in our report), but they have since updated their report to clarify that it is the King Poseidon role that Hudson has been cast in.