Jack Harcourt Deveraux and Jennifer Rose Horton are fictional characters and a supercouple from the NBC daytime drama Days of Our Lives, whose history spans from 1989 until 2012. The two have been portrayed by more than one actor/actress since their inception, but were originally, most recently, and most famously portrayed by Matthew Ashford and Melissa Reeves. Fans have nicknamed the couple "J&J" or JnJ" on internet message boards. For their portrayal of Jack and Jennifer's romance, Ashford and Reeves won Soap Opera Digest Awards for Favorite Supercouple in 1991 and Best Love Story in 1992.

A supercouple or super couple is a popular and/or wealthy pairing that intrigues and fascinates the public in an intense or obsessive fashion. The term originated in the United States, and it was coined in the early 1980s when intense public interest in fictional soap opera couple Luke Spencer and Laura Webber, from General Hospital, made the pair a popular culture phenomenon.