The former pin-up passed away in Burbank, California on 26 April (12), according to the New York Times.
Born in 1919, Stewart dropped out of college at Indiana University to become a model and she was quickly approached to shoot a World War II recruitment poster for the Army in a bid to boost enrolment in America.
The iconic sheet has since been reproduced over 94 million times, catapulting Stewart - often dubbed Uncle Sam's Poster Girl - into the spotlight for her wholesome image.
Due to high demand, the beauty travelled across the U.S. with stars like Fred Astaire and Judy Garland to sell war bonds, subsequently appearing in over 20 films, many of them uncredited. Her list of movies include parts in Wonder Man, Frank Sinatra's Step Lively, The Fallen Sparrow, and Gildersleeve's Ghost.
Towards the later part of her life, Stewart produced shows at iconic California concert venue the Hollywood Bowl for such artists as The Beatles, The Beach Boys and Barbra Streisand.