He wrote: “After the stories of Jango and Boba Fett, another warrior emerges in the Star Wars universe.
“The Mandalorian is set after the fall of the Empire and before the emergence of the First Order. We follow the travails of a lone gunfighter in the outer reaches of the galaxy far from the authority of the New Republic.”
Disney’s streaming service is designed to rival Netflix and will be the exclusive home for Marvel films as well as Pixar properties.
American actor and director Favreau, 51, known for starring in films including Swingers, The Break-Up and Couples Retreat, also has previous experience of working on the Star Wars franchise.
He had roles in Star Wars: The Clone Wars animated series and in Solo: A Star Wars Story.
Jon Favreau releases details of upcoming Star Wars TV series