The Twilight star takes on the role of Marylou, who accompanies husband Dean Moriarty (Garrett Hedlund) and narrator Sal Paradise (Sam Riley).
On the Road, which has been tipped to screen at this year's Cannes Film Festival, is based on Jack Kerouac's acclaimed Beat Generation novel and features Kirsten Dunst, Amy Adams and Viggo Mortensen.
The new Stewart image debuted on the movie's official website.
> On the Road trailer
Photo gallery - view the latest On the Road pictures: