When you go to see James Cameron's Avatar this weekend, you're not only buying a ticket to see this long awaited sci-fi masterpiece, you are also buying a ticket to see the very first Piranha 3D trailer. It is set to debut exclusively with the film this weekend. Here is the official press release:

Dimension Films will unveil the first trailer for the highly anticipated movie Piranha 3D in state-of-the-art 3D EXCLUSIVELY in theaters this weekend in front of Avatar. The brand new Piranha 3D trailer will be shown in 3D on selected prints of Avatar, and also in selected 2D locations.

RELATED: New Piranha Movie Happening, Concept Art Unveiled

Starring Elisabeth Shue, Jerry O'Connell, Jessica Szohr, Adam Scott and more; and featuring a special appearance by the silver screen's most famous foe of underwater predators, Richard Dreyfuss, Piranha 3D will hit theatres on April 16, 2010.

From acclaimed director Alexandre Aja comes the new action thriller Piranha 3D, in the latest eye-popping 3D technology. A new type of terror is about to be cut loose on beautiful Lake Victoria. After a sudden underwater tremor sets free scores of the prehistoric man-eating fish, an unlikely group of strangers must band together to stop themselves from becoming fish food for the area's new razor-toothed residents. But our heroine (Elisabeth Shue) is seriously outnumbered, and with only one chance to save the lake and her family from totally being devoured, she must risk everything to destroy the aquatic carnivores herself.

Piranha 3D is produced by Alexandre Aja, Gregory Levasseur, Mark Canton and Marc Toberoff. Executive Producers are Alix Taylor, J. Todd Harris, Bob Weinstein and Harvey Weinstein, Chako Van Leeuwen. Associate Producer is David Hopwood.