Fans think they've figured out who ‘invisible’ Friends character is as mystery takes a new turn

In many of our favourite movies and TV shows, there are a few inconsistencies in the storylines that just never get solved.

Viewers are left wondering whether these plot holes are planted for some kind of secret purpose, or whether production just never got round to tying up some of the loose ends.

If you're bored, you can have a field day looking for them with Friends alone - as the hit 90s sitcom is riddled with inconsistencies or 'easter eggs' - depending on which way you look at them.

There's that pretty large problem which Bruce Willis' cameo caused and the irregularities in Rachel Green's backstory, to name a few.

But a quarter of a century after it first aired, fans think they've finally got to the bottom of one of the bizarre mysteries featured in the ten-season sitcom.

Take a look at this clip here to jog your memory:

In the third episode of the sixth season of Friends, titled 'The One With Ross' Denial', Rachel (Jennifer Aniston) is desperately looking for a room to rent.

She got the boot from the iconic apartment she shared with Monica (Courteney Cox) as Chandler (Matthew Perry) is moving in, and she needs a place to stay, promptly.

Rachel hopes that Phoebe (Lisa Kudrow) will let her live with her, however, her pal informs her that there's no room at the inn.

Phoebe tells her mate that, unfortunately, she already has a housemate named Denise - and that's the first and last we hear of the mystery woman.

Denise never appeared in an episode of Friends or came up in conversation again, so fans were left to make their own conclusions about her identity.

The leading theory is that Phoebe invented an imaginary bunkie so that she had an excuse for Rachel not to move in - but that all might be about to change.

That's because someone on Reddit claims to have inside knowledge, which can bust the cold case about Denise wide open.

Viewers have shared all kinds of theories about Phoebe's mystery roommate over the years (NBC)

In a Friends-related forum, a social media user brought up the Denise debate.

The post read: "Was Denise a real person, or did Phoebe make her up?

"No one had ever heard of Denise before, and when questioned, Phoebe got defensive and stormed out.

"I used to think Phoebe lied about Denise so she wouldn’t have to live with a friend, possibly because she didn’t have the best experience living with Monica.

"But now, I’m not so sure. What do you guys think?"

There were dozens of responses which discussed theories about the forgotten Friends character, but one was particularly interesting.

The author of the post claimed to have been on the set of the hit show - to audition for the role of Denise.

A person who claims to have inside knowledge on the Denise debate shared their thoughts on Reddit (NBC)

The post read: "It’s definitely Mike’s (Paul Rudd) sister, I know because I auditioned for it.

"They were going to do a storyline with Joey (Matt LeBlanc) crushing on Mike’s two sisters but cut it out."

Reddit users were stunned by the alleged revelation, while others shared their wacky thoughts on Denise's true identity.

Another person said: "I think it’s part of Phoebe’s mystique, she has loads under her hat that the rest don’t know until they need to know."

"She had a whole husband that no one knew about, so yeah, I think Denise was real," someone else chimed in.

And a third added: "I feel pretty sure that either Phoebe made it up, or the writers made it up, not thinking people would notice. I don't think she was real."

As you can see, the debate is still raging on despite someone insisting Denise was in fact Phoebe's sister-in-law who's storyline never made the cut.

But what do you reckon?