Fox Filmed Entertainment announced this week that the trailer for James Cameron's upcoming 3D movie Avatar will be released in theaters worldwide and online on one day, August 21, 2009. The trailer will be in IMAX® 3-D, IMAX® 2-D, digital 3-D, digital 2-D, and 35mm 2-D, and online.

Select cinemas and IMAX® theaters will screen 3D extended footage on August 21 only, prepared by the renowned filmmaker for this global "Avatar Day" event. No mention has been made of which theaters will have this extended footage, but it makes sense that such details will be forthcoming.

The Hollywood Reporter's Risky Business blog is saying that the admission to the 15-minute screening of the footage will be free of charge. This information was in a report from the industry convention Comic-Con, where 25 minutes of footage from the movie was shown yesterday.

In Avatar, an ex-Marine finds himself thrust into hostilities on an alien planet filled with exotic life forms. As an Avatar, a human mind in an alien body, he finds himself torn between two worlds, in a desperate fight for his own survival and that of the indigenous people.

The movie opens in conventional theaters and IMAX theaters on December 18, 2009.

Source: Fox Filmed Entertainment Press Release. Thanks to reader Ron H. for sending us the link to the additional report from THR!