The reveal of 'A's' identity is drawing ever closer, and two members of the Pretty Little Liars cast are in on the secret.

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For four and a half seasons, 'A' has remained an elusive figure on the ABC Family series. The baddie can't stay hidden forever, however, and the truth might be just around the corner.

"Found out who THE -a is," tweeted Keegan Allen (Toby) in early September. "Whoa. I'm... speechless. So I decided to tweet instead."

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As the Halloween special approaches, a new teaser makes it seem as if Troian Bellisario (Spencer) knows as well. Is the onscreen couple in the know because they are integral to revealing the truth, or are all the Liars privy to this privileged information?

Fans won't be tortured by the mystery much longer, however. Showrunner Marlene King told a viewer that the answer is "closer than u think," and perhaps Bellisaro and Allen know because the reveal will come during the second half of season 5.

Find out more when Pretty Little Liars returns to ABC Family during the "12 Days of Christmas." Click the video below to get a sneak peek at "How the 'A' Stole Christmas."