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18 April 2015 Last updated at 09:35 BST
The 22-year-old actors, Daisy Ridley and John Boyega, were introduced at an official fan convention in California.
Star Wars Episode VII: The Force Awakens is due to be released on 18 December.
BBC London's Victoria Hollins reports on the latest instalment of the Star Wars saga and its newest recruits.
Two young Londoners are to share the limelight with Harrison Ford when the hotly anticipated new Star Wars film opens.