The stars of Tv comedy The Big Bang Theory are set to mark 'Star Wars Day' on 4 May (14) with a very special episode.

Writers have teamed up with Lucasfilm special effects experts for a themed special that will air in America three days before the unofficial geek holiday.

In the Proton Transmogrification episode, the Tv show's regulars will celebrate Star Wars Day, and Tv veteran Bob Newhart will reprise his Emmy-winning role as Arthur Jeffries.

The Lucasfilm Industrial Light + Magic technicians will recreate Star Wars sage Yoda's home planet Dagobah for the special episode.

The Big Bang Theory's creator Chuck Lorre says, "We were approached by the Lucasfilm people to do something to celebrate Star Wars Day, which was nice."