Dr. Horrible's Sing-Along Blog Debuts on The CW — Watch the Promo Now! (VIDEO) Tweet October 8, 2012 at 09:45AM EDT by Wetpaint Entertainment Staff Related: Castle, Nathan Fillion Credit: YouTube Dr. Horrible's Sing-Along Blog, directed by Joss Whedon and starring Castle's Nathan Fillion, will make its television debut this Tuesday, Oct. 9 at 9 p.m. ET on The CW. Will you tune in?
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