Scrubs Season 3 Episode 17: "My Moment of Un-Truth"
Carla has dinner with an old crush and asks J.D. not to say anything; Elliot's patient, Mr. Thompson (Alexander Chaplin), refuses to take drugs, but Cox tries to convince her that Thompson is a drug addict.
J.D.'s Narration: I guess you can never underestimate how the smallest gesture can make everything better. J.D.: You know, for a minute there I actually thought you had a twin brother. Janitor: Really? J.D.: Mm. Janitor: Was it when my twin brother was here? J.D.: Stop it.