The original Darth Vader costume became a cinema classic

The DVD will feature an interview with Star Wars creator George Lucas as well as a peek at the costume worn by Anakin Skywalker, who becomes Vader.

Star Wars: Episode III is to be released in 2005.

"Our fans have been eagerly awaiting every morsel of Episode III as we divulge it," said Lucasfilm's Jim Ward.

"We're giving it to them piece by piece," he said.

"We're going to see the evolution of this character and go places with Darth Vader we've never gone before."

September release

The featurette will also show behind-the-scenes footage of Hayden Christensen (Anakin Skywalker) and Ewan McGregor's (Obi-Wan Kenobi) lightsaber battle at the end of the film.

The original trilogy DVD will be released in September. It has already climbed to the top of the DVD charts on internet retail sites, such as Amazon, through pre-orders.

The trilogy will also include a look at the lightsabers, biographies of some of the famous alien creatures and a playable Xbox videogame demo for the upcoming game Star Wars: Battlefront.

But the preview will not divulge all the secrets of the film, which will be released in cinemas in May next year.

The film is the final one in a series of three, which started with 1999's The Phantom Menace, set years before the events of the original Star Wars trilogy.