Back to the Future fans are only just realising hidden detail in third film 35 years later

Back to the Future is a cult classic 1985 film which features teenager Marty McFly who accidentally travels from 1985 to 1955 in a time machine built by his eccentric friend, Dr Emmett Brown.

However, when he travels to the past, he has to ensure that his parents fall in love again so he can secure his future - otherwise, he may find that life as he knew it is no longer the same.

It's a real race against time, and if you haven't seen it before but fancy giving it a whirl, you'll find no more spoilers here!

The film was so successful, becoming the highest-grossing film of 1985 and receiving widespread acclaim from critics and fans, it led to two sequels - Back to the Future Part 2 in 1989, and Back the Future Part 3 in 1990. The films are so popular with audiences they still hold up to this day.

Despite being 35 years since its release, there's an amusing detail that people are just spotting in the third installment, which takes place in the Old West.

Taking to Reddit's Movie Details thread, a movie fan penned: "In Back To The Future 3, Doc's son Verne motions the camera in for a closer look and points at his dangly bits". They also posted the video so people could see for themselves.

And, while yes, it does appear that Verne, played by Dannel Evans, was pointing at his "dangly bits," there was a good reason for this - as it was a secret signal that the behind-the-scenes crew likely would've understood.

In the comments, someone explained: "He was signalling to the crew that he had to go to the bathroom. Source: My friend did some editing for a commercial and met Christopher Lloyd, and this was the only thing he wanted to know".

Another said that it can't have been that because he "smirked" while doing it.

However, a Redditor justified this by saying: "No idea why the smirk. I can only guess that maybe the kid had accidents in previous shots amd the someone told him to do that move if he had to go again, and maybe when he does the finger thing it makes him laugh a little bit in his head".

"I remember hearing about this years ago, now I can't watch the end of this movie without thinking about it," somebody shared.

According to Complexions Dance, the theory one of the Redditor's had was actually correct, saying it's about 1 hour and 50 minutes into the film.

The website shares: "Verne raises his right hand, inviting someone closer, then points his index finger down with a mischievous glint". They said it looked like a "cheeky joke," but confirmed that the "real story is even funnier" as he was "hinting he urgently needed a bathroom break".

"These kinds of behind-the-scenes quirks often vanish in the whirlwind of the movie's bigger moments. Most eyes focus on Doc chatting with Marty and Jennifer, unaware that this small slice of authenticity and human spontaneity made the final cut," they confirmed.

They said that it's a "a playful reminder that even in iconic films, actors are people with real needs and personalities behind the scenes".