S1m0ne (2002)

The career of a disillusioned producer, who is desperate for a hit, is endangered when his star walks off the film set. Forced to think fast, the producer decides to digitally create an actress "Simone" to sub for the star--the first totally believable synthetic actress. The "actress" becomes an overnight sensation, with a major singing career as well, and everyone thinks she's a real person. However, as Simone's fame skyrockets, he cannot bear to admit his fraud to himself or the world.