Friends viewers astounded after spotting mistake that can only be seen on certain screens

Many of us will find ourselves scrolling through all the streaming sites looking for something new to watch, only to eventually settle on Friends yet again.

After all, it’s an easy-going comfort watch, with jokes that have stood the test of time – well, most of them – and a digestible runtime of under 30 minutes for each episode.

With every watch often comes new revelations, as we revisit some of our old favourite instalments and spot something different each time.

In one 2002 episode, you may have found yourself to oblivious to a particular glaring mistake, as it’s only actually visible on certain screens.

‘The One in Massapequa’, from season eight, saw Monica and Ross’ parents throw a lavish 35^th wedding anniversary party.

At one point, Ross (David Schwimmer) and Rachel (Jennifer Aniston) arrive at the bash, and head over to a table where presents are being left for the Gellers as Jack (Elliott Gould) chews away on a party snack.

However, the camera suddenly cuts to Ross and Rachel’s reactions, and we can see it’s not Jack they’re speaking to, but a total stranger.

It looks like Gould was replaced by a stand-in actor, and while the blunder wouldn’t have been visible in the original standard 4:3 aspect ratio, with modern audiences now viewing it in a wider aspect ratio of 16:9, it soon becomes apparent.

The bizarre issue was spotted by Reddit user 1channesson, who shared a clip on the site as others pointed out what the problem likely was.

It turns out to be pretty common, too, with one person commenting: “There are a few other scenes I’ve scene (over the last year or two) made mention of, with stand-ins suddenly appearing on screen.”

Well, this is awkward (Warner Bros)

“I recall one involving Rachel in her and Monica’s apartment, now with the wide screen release, shows the stand-in instead of Jennifer Aniston.”

Recently, Aniston cleared up some similar confusion from another moment in season three's 'The One Where No One's Ready' episode.

The plot sees Ross frantically try to round up the gang for a special event at his museum.

Rachel emerged in a green dress... but was it green? (Warner Bros)

Anyone who has watched the series the first time around will remember that the dress was green, but Max's shiny new 4K restoration depicts the gown in a totally different colour.

Amid the chaos, Rachel finds she has nothing to wear, causing even more of a meltdown from her boyfriend, before she finally emerges from her room leaving him speechless in a stunning floor-length gown.

The 4K revamp left many fans baffled (Warner Bros)

Max seemingly acknowledged the difference in an Instagram post showing a side-by-side shot of the HD picture showing the dress to be green, while the 4K revamp showed it to be blue.

Eventually, Aniston put all the speculation to rest once and for all after taking to her own Instagram story to share with her 44.8 million followers what the actual colour of the iconic dress really was.

Resharing the Max post, she confirmed: "For the record, the dress was mint green."