Apple is now selling JJ Abrams' Star Trek Into Darkness on the iTunes Movie Store three weeks ahead of its September 10th general release.

The film is available in HD for $20 and SD for $15, or as a $25 HD bundle with the prior Star Trek film. There is no rental option -- rentals will be available September 10th -- and it appears to only be available to U.S. iTunes customers.

J.J. Abrams STAR TREK INTO DARKNESS is the best-reviewed blockbuster of the year. When a ruthless mastermind known as Khan (Benedict Cumberbatch) declares a one-man war on the Federation, Captain Kirk (Chris Pine), Spock (Zachary Quinto), and the daring crew of the U.S.S. Enterprise will embark on the greatest manhunt in history. It will take all of their skills and teamwork to defend Earth and eliminate Khan’s threat in this “sleek, thrilling epic.” (Owen Gleiberman, Entertainment Weekly)

A number of independent or smaller-budget films have launched day-and-date or even ahead of their theatrical release on iTunes, but the three-week early purchase window ahead of a DVD/Blu-Ray release is part of an effort by the major studios to jumpstart more profitable digital sales. Apple has offered early streaming access to music albums in the past.

Star Trek Into Darkness is available in HD on iTunes for $20. [Direct Link]