FRIENDS fans have been left stunned after spotting a major plot hole involving Ross Geller – nearly 30 years after the episode first aired.

The sitcom, which first hit screens in 1994, has remained one of the most popular comedies of all time.

But even the best shows have their blunders, and one social media user thinks they’ve found a glaring mistake in Friends.

Over the years, eagle-eyed viewers have questioned things like how Monica and Rachel could afford their spacious New York apartment or why Ross seemed to be 29 years old for multiple seasons.

However, this latest discovery concerns Ross’ romantic history – and it’s left some fans scratching their heads.

In Season 1 Episode 23, while Carol is giving birth Ross makes a heartfelt confession, telling his friends: "My first time with Carol was my first time."

But fast forward to Season 7 Episode 4, and suddenly things don’t add up.

During a hilarious shouting match between Ross, Monica, and Chandler, some embarrassing secrets are spilled – including that Ross once had an intimate encounter with the cleaning lady in his and Chandler’s college dorm.

Fans were quick to call out the contradiction, with one commenting on YouTube: "Well, I’ll be damned. Never noticed that."

Another joked: "Judging by his reaction, he seemed to have forgotten it, so not much of a plot hole."