After years of speculation and delays, Jurassic Park IV is finally moving forward with director Colin Trevorrow (Safety Not Guaranteed), who was confirmed to take the helm last month. While details are still scarce on the story, paleontologist Jack Horner revealed there will be a new dinosaur on display in this sequel.

"I can't actually tell you who that will be. But you'll want to keep the lights on after you see this movie."

Jack Horner served as the dinosaur adviser on the original Jurassic Park, which comes back to theaters in 3D April 5. He is returning to consult on this sequel, which will be produced by Frank Marshall and Patrick Crowley, with Steven Spielberg serving as executive producer.

Colin Trevorrow is directing from a screenplay by Rick Jaffa and Amanda Silver (Rise of the Planet of the Apes). It isn't clear when production will begin at this time.