The touching true story behind Onward – how a real-life loss inspired the Pixar movie

"When I was a year old, my father passed away," Scanlon told the crowd at Disney’s D23 conference in 2017. "I don't remember him and neither does my brother, who was three at the time."

"I have always wondered who my father was. And that question became the blueprint for this movie."

In the film, it’s blue elf Ian who struggles with having never met his father, an accountant who passed away before he was born and while older brother Barley was a toddler.

And producer Kori Rae recently gave a bit more detail about how Scanlon’s family story inspired the movie.

"People would always ask him, don't you miss your father?” Rae told RadioTimes.com and other journalists at a 2019 preview event.

"He always answered, 'Well I never knew him.' And one time he was talking to his mom and his mom said 'Well that's the saddest part, you aren't able to miss him because you never met him.' And so there was a lot of that deep personal work that he was doing, and it kind of just started from there.

"That's kind of where it originated in terms of him kind of asking those questions," Rae added. "How am I like my dad? Who was he and how am I like him? And kind of like, who am I? That was kind of the genesis of it."

The finished story – which sees the brothers use long-forgotten magic to bring their father back for a day, only for the spell to go wrong and only bring his legs back to life – obviously takes a few liberties with the source material, however.

"Growing up without a dad, every little piece of information I learned — his favorite colour or his favorite food — was a piece of him that I could put him together with," Scanlon told C & G News.

"We thought, what if they literally had a living piece? And that’s where the idea of the pants came up."

The contrasting personalities of timid Ian and brash Barley were also a new invention for the film, with Scanlon noting that in real life both brothers are a bit more reserved with less of a clash.

"My brother actually isn’t like Barley in characterisation at all," he said. "My brother is also very shy and thoughtful, and he’s a computer programmer. He’s very responsible."

"I think Dan is definitely Ian," Rae added. "Barley is a little more of a caricature, just to kind of play those opposites. Dan’s brother is absolutely lovely, and really nice. But that didn't make for a very enervating story!

"We'd be in the story room and Dan would just be like ‘Yeah but my brother was so nice to me...’ we're like ‘That doesn't work, that's no fun. Nobody wants to watch that. Nobody wants to see two brothers famously getting along.’

“So we mucked around a little bit,” she said.

Still, amidst all the magic, quests and added dramatic weight, there was one part of Scanlon’s story that’s almost directly translated into the film. When he and his brother were teenagers, while they didn’t receive a magic staff from their father (as Ian and Barley do in the film) they did get given a recording of his voice for the first time, taken by a relative at a wedding.

Unfortunately, after hours of scouring the tape it was discovered that Scanlon’s father only said “Hello!” and “Goodbye!” very quickly – but even that was something they hadn’t had before.

“I learned a lot about what kind of person he was by the way he said 'Hello' nervously and excited, and then the way he said 'Goodbye' is a little shy and awkward," he said. "[I thought], 'Oh, he’s like me. He’s an introvert.'"

In Onward, Ian similarly plays and replays a recording of his father’s voice when he misses his presence most deeply – though in this case the recording is longer and with more responses, meaning that he’s able to have a form of conversation with his long-dead parent in a particularly touching scene.

"Dan's story was a huge part of it, and it kind of laid the groundwork, and opened it up to expand on his story and make it a universal story about connection, about family," Rae said.

"Dan was a little bit reticent to always be coming at it from his own point of view, and we kept having to encourage him to really keep tapping into the personal aspect of the story. Because he was just worried it was going to become too autobiographical or something.

"So I had a lot of really really great times with all of us sharing our personal stories, so it wasn't necessarily just Dan and we were making a film for the world.

"But I think his personal story... everybody on the team, it just resonated with everyone," she concluded.

"When you tell a personal story, chances are even if people haven’t had the exact experience you had, they have had something like it, and if it comes from that true place, it’s probably going to touch people in one way or another," Scanlon agreed.

"So, they would tell us all their great stories, and we’d incorporate them."

Onward is in UK cinemas now