Jerry Seinfeld's Mad About You Cameo Fueled Fan Theories Of A Shared Sitcom Universe

During an NBC brainstorming session in 1993, then-promo producer Dan Holm created a catchy new slogan that would come to define the 90s: "Must See TV" (via Esquire). The name stuck, and while the shows that were considered "Must See TV" changed, for most of the 90s, it was whatever aired in the coveted 8 pm — 10 pm ET time slot. "Seinfeld" was part of that slot from 1993 to 1998, and "Mad About You" from 1993 to 1995. "Friends" became a permanent member of the club after first airing at 8:30 pm ET in 1994.

Most people are aware that "Friends" and "Mad About You" shared the same world, as Lisa Kudrow appeared as Ursula Buffay in Season 2, Episode 4 ("Married to the Job"), and would go on to make a total of 23 appearances as Phoebe's twin sister before "Mad About You" ended in 1999. Helen Hunt and Leila Kenzle would also make an appearance of their own on "Friends" in Season 1, Episode 16 ("The One with Two Parts Part 1"), when Jamie and Fran head to Central Perk and mistake Phoebe for Ursula. But there's an uncredited cameo by Jerry Seinfeld in "Mad About You" that has fans wondering if all three sitcoms have a shared universe.

In Reddit's Today I Learned subreddit, u/jscari started a conversation that began with "TIL [Today I learned] "Seinfeld," "Mad About You," and "Friends" all exist in the same universe" and inspired a dialogue that included over 1000 comments. Few would argue that "Mad About You" and "Friends" share the same world, but it gets tricky when "Seinfeld" is brought up. Many would assume at the least it's connected to "Mad About You" due to Jerry Seinfeld's appearance in Season 7 when Paul (Paul Reiser) and Ira (John Pankow) run into him on the street or an earlier Season 1 appearance by Kramer (Michael Richards), who Paul is subletting his apartment to. But several examples contradict this theory.

In 1994, NBC's executives had the brilliant idea of "Blackout Thursday," beginning with Jamie on "Mad About You" causing a city-wide blackout that would also affect "Friends," "Seinfeld," and "Man of the People." "Seinfeld" famously refused to participate, with writer Jeff Schaffer recalling to UPROXX that "They started pitching it to Larry and 'No.' [laughs]. When he told us, I said, 'Fastest no in show business?' And he goes, 'Yup. No, we're not doing that.'"

Fans also point to Courteney Cox playing Seinfeld's girlfriend Meryl on "Seinfeld" and Jason Alexander as Earl on "Friends." "And George hates watching "Mad About You" with Susan when they're engaged," wrote u/klsi832. Whether or not "Seinfeld" was part of the same universe, or just when it was convenient, is something that could be debated for a long time.