Storybrooke's in for a zombie invasion.
According to TVLine, Sonequa Martin-Green -- who plays a prisoner named Sasha on "The Walking Dead" -- has joined the cast of "Once Upon A Time" as a mysterious character named Tamara.
The details of Martin-Green's appearance on the fantastical ABC series have yet to be disclosed, but TVLine reports she's rumored to have a British accent.
In addition to "The Walking Dead," Martin-Green has also appeared on "The Good Wife," "Gossip Girl," "NYC 22" and "Army Wives."
Once Upon a Time returns to ABC on Sunday, Jan. 6 at 8 p.m. ET on ABC.