The X-Files

Rebecca Toolan, who plays Fox Mulder's mother, is in reality only one year older than David Duchovny.

During the opening titles, in the Mulder and Scully's FBI ID badges can be read "Federal Bureau of Justice, United States Department of Investigation." This alteration was necessary as making a fake FBI badge, even for fictional purposes, is illegal. The real-life quote is: "Federal Bureau of Investigation, United States Department of Justice."

In the early years of the series, Mulder is a firm believer in extraterrestrials and Scully is skeptical. In real life this is the opposite, being Duchovny the skeptical and Anderson the believer.