The 'Death Proof' beauty - whose boyfriend Robert Rodriguez is set to direct the film - has been chosen to play the cult heroine made famous by Jane Fonda in the original 1968 erotic space adventure.
McGowan was used by Rodriguez in tests shots for the film, and he was so impressed by the 34-year-old star he decided to cast her.
The sexy actress, who previously dated Marilyn Manson, will now don Barbarella's iconic fur bikini to portray the Queen of the Galaxy.
A series of Hollywood actresses including Sienna Miller, Kate Beckinsale, Angelina Jolie and Halle Berry have previously been linked to the role.
McGowan met Rodriguez when she starred in his film 'Planet Terror', and the pair are rumored to be engaged.
In the original movie, Barbarella dons various skimpy outfits for her sexy space adventure.
Producer Dino De Laurentiis said recently: "The reinvented heroine will be akin to a female James Bond - in outer space."