3rd Rock from the Sun - Season 6 Episode 4 : Dick'll Take Manhattan (1) 2001

The Solomons visit a parallel universe, in which they are living in New York City, where Dick is a highly regarded attorney, Sally writes a sex column and Harry is President of NBC, while Tommy is a star on Saturday Night Live. Despite this, Dick is unhappy because he cannot find Mary; however, upon entering a basement bar he discovers her, a failed actress-turned torch singer who has renamed herself Kiki Lyle. Meanwhile, Sally discovers that Don is the Mayor of New York, and that she isn't his girlfriend, but his mistress.