Leonard Nimoy will reprise his role as Mr Spock in J J Abrams' upcoming Star Trek feature for Paramount, the director announced on the opening day of Comic-Con in San Diego.

Meanwhile Zachary Quinto, one of the stars of this year's hit US television series Heroes, will portray the Vulcan in his younger years.

Both actors made surprise appearances at Paramount's slate presentation, along with producers Damon Lindelof and Bryan Burk and writers Roberto Orci and Alex Kurtzman. Star Trek will open on Dec 25, 2008.

Meanwhile Steven Spielberg told fans via satellite link from the set of the fourth Indiana Jones instalment that Karen Allen, who played Harrison Ford's love interest in Raiders Of The Lost Ark 26 years ago, was joining the cast. Ford stars alongside Ray Winstone, Cate Blanchett and Shia LaBeouf. The film opens over Memorial Day 2008.

Fans were also treated to footage from Jon Favreau's Iron Man starring Robert Downey Jr, which is set to open on May 2 2008, as well as Robert Zemeckis' epic adventure Beowulf for Paramount, Shangri-La Entertainment and Warner Bros. Beowulf stars Winstone and opens on Nov 16 this year.

Producer Judd Apatow and director Steven Brill sent a taped greeting to introduce the first screening of the trailer for the upcoming Owen Wilson comedy Drillbit Taylor, which opens on Mar 21, 2008.

On the eve [July 25] of the annual popular culture convention it emerged that Patrick Wilson, Billy Crudup and Jackie Earle Haley had joined Zack Snyder's graphic novel adaptation Watchmen.

The long-gestating project has seen a number of film-makers and stars come and go, and charts the fortunes of a group of redundant former superheroes who may be the targets of a conspiracy. The film is due to open next year.