Julianne was almost unrecognisable when she was spotted on the set of Game Changes, an HBO TV movie in which she portrays former U.S. vice presidential candidate Sarah Palin.
Production assistants desperately attempted to shield the actress from prying eyes in order to protect the integrity of the film as she headed back to her trailer.
Last week a promotional picture was released by HBO, who are making the film, of Julianne dressed in the famous red suit jacked worn by Sarah on the 2008 presidential campaign trail.
The upcoming HBO film is based on the political tell-all book of the same name, which gives a behind-the-scenes look at the US 2008 general election.