The Melancholia actress plays Camille in Walter Salles's upcoming film, a character based on real-life writer Carolyn Cassady.
Asked about starring an such an iconic project, Dunst told Digital Spy: "Luckily I'm not playing Jack Kerouac! I only have a small part in the film."
She added of Cassady: "She wrote a book called Off The Road, so I had my own personal bible that I could reference, She's a really great writer herself."
Watch Kirsten Dunst talk to us about On The Road below:
Dunst is joined in the film by Sam Riley, Garrett Hedlund, Kristen Stewart, Viggo Mortensen and Amy Adams. The movie, which wrapped in May, is being produced by Francis Ford Coppola.
Riley, who leads the film as Kerouac's alter ego Sal Paradise, has predicted that "there will be a lot of haters out there because the book means a lot to people".
Hedlund, who plays Dean Moriarty, has claimed that Stewart's portrayal of Mary Lou in the film is "incredible".