A price hasn't been announced yet. The service is expected in late 2019 after Disney's current deal with Netflix expires.
Previously Disney announced the inclusion of just Disney and Pixar movies and Disney TV shows. Adding the Star Wars and Marvel movies could make the new service appealing to teenagers and adults. The Marvel movies include the Avengers and Guardians of the Galaxy franchises.
The service will also have original Disney movies, TV series and shorts. Disney CEO Bob Iger said thousands of TV episodes and hundreds of movies will be available, though shows from Disney's ABC network aren't coming to the service.
Disney said last month that it was considering moving Star Wars and Marvel to the new service, but a decision wasn't announced until Thursday.
Disney did not say whether all the Star Wars movies dating back to the 1977 would be available on the service, or all the films in the Marvel universe. A spokesman had no immediate comment. Netflix also has a TV series based on Marvel characters, and Netflix said Thursday that relationship continues. As with the Disney and Pixar movies, Marvel and Star Wars movies that play in theaters in 2018 will be on Netflix for US viewers, and some films will be available into 2020.
Disney's offering is one of many online film and TV options coming from entertainment and tech companies, with more in the works. Disney, for example, is also launching an ESPN sports streaming service early next year. It won't replicate what's on ESPN, for now, so it's expected to be somewhat niche.
The company's shares slid $4.05, or 4 percent, to $97.46 (roughly Rs. 6,230) in Thursday afternoon trading. Investors may have sold because Iger said earnings per share for this fiscal year will be similar to the level for the year that ended on October 1, 2016. Wall Street analysts had predicted growth.