Who is 'A'? The question that has plagued Pretty Little Liars for five seasons will soon be a mystery no more.

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There is less then two weeks to go before a major 'A' reveal in "Welcome to the Dollhouse," and series creator Marlene King believes there is no way for fans to brace themselves for the final moments.

"Just re-watched the ending of the finale --- you guys just can't be prepared," King tweeted on Monday. "It's impossible. Even I'm not prepared."

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The Internet is going wild with 'A' theories, and King recently promised that many viewers are incredibly close to guessing the true identity of Rosewood's most notorious killer. For now, however, viewers must stay as in the dark as the Liars themselves (assuming no one from Alison's old clique is truly the series' big bad).

"It's so hard for me to answer most of your questions without giving up the identity of 'A,'" King teased during a post-episode Twitter chat on Tuesday. "That's how close you are."

We want to hear your theories - give us your best take on the 'A' mystery in the comments below!

Find out more when Pretty Little Lairs airs Tuesdays at 8 p.m. ET. Click the video below to see a preview for the penultimate episode, "I'm a Good Girl, I Am."