Disney fans have only just found out about vital last minute change in Finding Nemo that changed movie's fate

Disney fans are only just learning that Pixar made a 'heart-wrenching' last minute change to Finding Nemo.

It's not a reach to say the animated kids' movie is generation-defining - yet it would've been totally different if kept in its original form.

Finding Nemo follows clownfish Marlin on a treacherous journey to find his young son who gets lost in the depths of the ocean.

And along the way, he faces terrifying sharks and even befriends Ellen DeGeneres - oh sorry no, I mean, Dory the blue tang.

The movie captured the hearts of all ages upon its release in 2003.

Finding Nemo might not have hit the same if it wasn't for this last-minute change (Pixar)

Disney had already released major titles including Toy Story, A Bug's Life, Toy Story 2 and Monsters Inc by this point, so the pressure really was on.

Fortunately, it went on to be a huge success, and is still scoring 99 percent on Rotten Tomatoes to this day.

But Pixar animator Jason Deamer, who worked on Finding Nemo, revealed the story we all know and love could've actually been told in a totally different way.

Previously speaking to UNILAD, Deamer - who has worked at Pixar for 26 years now - explained: "Originally you found out [about Nemo's mom's death] through flashbacks. We all went to the last screening before it was going to be finished, and we all walked out the theater and no one was saying anything... "

"[We thought] 'Did we just just make our first bad movie?'

"We were a little concerned, and Lee Unkrick said 'Let me try something', and he took those flashbacks and he recut them all in the beginning."

Need a refresher? Tissues at the ready, the emotional scene is below:

Deamer went on to explain why the small change 'made the whole thing work'.

"When you didn't know [about Nemo's mom's death] in the beginning, you thought Marlin was an overprotective, annoying character," he said.

"It was the same footage. We didn't animate anything new. [Unkrick] just told the audience that sooner. I know it's heart-wrenching, but otherwise you just didn't empathise with [Marlin's] overprotective behavior."

In regards to why Pixar movies have such tearjerking scenes like the one in question in Finding Nemo, Deamer insisted that movie creators are 'not trying to hurt your feelings'.

Animator Jason Deamer has worked at Pixar for 26 years (Disney/Supplied)

"They're trying to make you understand where characters are coming from," he explained.

I don't think I'll be able to watch Finding Nemo in the same way again!

Interview conducted by Niamh Shackleton.