Friends fans baffled after learning origin of Phoebe's twin

Friends fans all know Ursula's story, right? She's Phoebe's rude twin, introduced in the first season of the show and played also by Lisa Kudrow, who was responsible for bringing Phoebe to life.

This isn't news to anyone who's seen the show - but what you might not know is that Friends isn't where Ursula originated.

As someone who has the entire boxset for the sitcom, who's seen every episode multiple times, and who could recite pretty much every scene without fail, I can confirm this has left me well and truly mind-blown.

The news about Ursula's origin isn't exactly a secret, but it's something that was easily missed if you became a fan of Friends in the years after it first started airing in 1995.

Kudrow discussed the story behind Ursula in a new interview with Modern Family star Jesse Tyler Ferguson on his Dinner's on Me podcast, on which Ferguson said he was 'very confused' about the 'genesis' of Phoebe, because Ursula already existed.

Offering further explanation to anyone still in the dark, Ferguson then revealed that Ursula was a character on the sitcom Mad About You, which ran from 1992 to 1999 and therefore overlapped with Friends.

Lisa Kudrow played Ursula before playing Phoebe (Jamie McCarthy/Getty Images)

If you're a fan of Friends, you might recognize Mad About You star Helen Hunt thanks to her guest appearance in Friends when she mistakes Phoebe for Ursula, who was a waitress in her own sitcom.

Still with me?

To explain Kudrow's ongoing appearances in Mad About You, Ursula's character was introduced in Friends as Phoebe's twin.

Hoping to shed more light on the character decisions, Ferguson asked Kudrow: "When did those two worlds connect? When did they decide that these two people are sisters, and then have Ursula actually come in to Friends?"

Kudrow played both Phoebe and Ursula (Warner Bros.)

Kudrow then explained that once Friends had been picked up, it was decided that the sitcom would air straight after Mad About You on Thursday nights.

"I was still being asked to appear on Mad About You... It was decided that [it was] Phoebe's twin sister, they both are in New York," Kudrow explained, before revealing that her role as Ursula had helped her land the role of Phoebe on Friends.

"[Mad About You co-producer] Jeffrey [Klarik] told David [Crane, Friends co-creator], 'you know who you should see for Phoebe, is the girl playing Ursula', and he said 'yeah she is funny'."

Friends fans have been left stunned by the revelation, with one writing: "Hold up! Ursula was a pre-established character on a different show?"

"I literally watch Friends every single day and have watched since day 1 and I had no idea Ursula already existed," another added, as a third wrote: "Love this! I had no clue."