After years of confusion, two Friends writers have explained the real meaning behind Rachel's "it IS a big deal" joke. Once the darling of NBC's comedy lineup, Friends has remained one of the most beloved sitcoms of all time thanks to streaming and endless reruns. It tracks the lives of six friends living in New York City and is responsible for numerous iconic one-liners and references. While some might argue that parts of Friends haven't exactly aged well, it has definitely cemented its place in pop culture history. Undoubtedly, one of the most iconic parts of Friends' legacy is the off-again, on-again relationship of Ross (David Schwimmer) and Rachel (Jennifer Aniston).

The season 4 premiere, "The One With the Jellyfish," starts with Rachel and Ross on-again, having gotten back together during a weekend trip to Montauk. Their reunion was contingent on Ross reading an 18 page letter Rachel wrote baring her feelings; however, though Ross tells Rachel he read it, he actually fell asleep midway through. It isn't until the couple is back in New York that the truth comes out, and the two have a brutal fight. As Ross storms out, Rachel gets the last word by yelling, "It's NOT that common, it DOESN'T happen to every guy, and it IS a big deal!"

Related: What Happened To Ross & Rachel After Friends Ended

For years, Rachel's parting line has baffled Friends fans, as what she's referring to is never really explained. Luckily, however, executive producers Greg Malins and Adam Chase have finally elaborated on the joke with EW. Malins first came up with it, and Chase revealed that the line actually is in reference to a moment from the season 2 episode, "The One Where Ross and Rachel... You Know." "They were insulting each other back and forth," Malins explained, "and I had this idea in my head, [Rachel] says, 'Well one time, when you prematurely ejaculated, I told you it was okay and it wasn't."

Ross and Rachel's first date at the museum in Friends

Malins also shared that this joke was the first one he ever wrote down before pitching. "I remember thinking, 'If I don't pitch this exactly right, it's not gonna get in," he recalled. The "it IS a big deal" portion came from Chase, who explained that the Friends writers' room was very collaborative. Now, years later, the mystery has been put to rest, though some might have already put together what Rachel was referring to. Capping off the already hilarious moment was Chandler (Matthew Perry) declaring, "I knew it!" Knowing what Rachel was talking about only makes Chandler's reaction funnier.

This just shows that even a beloved show like Friends has more secrets to reveal. Perhaps fans will be blessed with more behind the scenes stories like this when the Friends cast makes their long-awaited reunion on HBO Max. That special is still unfortunately on hold, though fans were treated to a mini-reunion last week at the Emmys, when Aniston joined forces with Lisa Kudrow and Courteney Cox. As the wait for the true reunion continues, fans can rest assured that at least one major Friends question has been answered.

More: Friends: Ross’ Ex-Wife Actor Almost Played Rachel Instead of Jennifer Aniston

Source: EW