Sandra Vergara is joining the cast of Fright Night, DreamWorks’ remake of the 1980s teen horror cult classic being directed by Craig Gillespie. Vergara, the sister of “Modern Family” star Sofia Vergara, will play the girlfriend and assistant to a magician, played by David Tennant, reluctantly recruited by Anton Yelchin to fight off a vampire. Colin Farrell, Toni Collette, Christopher Mintz-Plasse, Imogen Poots also star. The original Fright Night, written and directed by Tom Holland in 1985, was a horror comedy about a teenager who discovers that his neighbors are vampires. DreamWorks will release the redo in theaters October 7, 2011.