Supernatural is gearing up for the 200th episode, and the "zany" milestone's musical plot caught the cast by surprise.

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Sam (Jared Padalecki) and Dean (Jensen Ackles) will investigate a haunted Carver Edlund play during the "musical-ish" installment, a direction Padalecki and Ackles never thought the series would take.

"It's still along the lines of, 'What?' I haven't changed my mind," Ackles told VanCon attendees in regards to his previous apprehension about the idea. Despite this, the actor believes fans "will be pleasantly surprised. Or maybe you'll just be completely pissed off."

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As the cast continues to film for "Fan Fiction," both the fans and actors can't help but draw parallels between the 200th and season 6's "The French Mistake."

"We thought we were taking a chance with 'The French Mistake.'" We thought, we were like, this is either going to oddly do well or its going to flop and blowup in our face, and I think it oddly did well. This particular episode, in my opinion, has a very similar zany feel to it."

Find out more when Supernatural returns to The CW on Oct. 7. Click the video below to see Demon Dean and Sam reunite.

Tags: supernatural television CBS