Former “Home Improvement” star Jonathan Taylor Thomas, 19, is preparing to have his own primetime show. The Hollywood Reporter has announced that the actor, who once received 50,000 pieces of fan mail a month, has signed a deal with Fox Broadcasting Co. and 20th Century Fox TV to develop his own series, though it remains to be seen whether it will be a comedy or a drama. Since appearing on the Tim Allen sitcom for seven seasons, Thomas’s projects have included starring in a Showtime original drama, “Common Ground,” which focused on attitudes toward gay rights. He has also filmed “Speedway Junkie,” a new movie by director Gus van Sant (the remake of “Psycho”).