'Love Actually' filmmaker Richard Curtis makes first foray into animation

"My theory is that it means that people working in animation are nicer than people working in normal movies, because they know they've got to get on for five years.

"You really do get married. It's not a one night stand—it's not a sexy holiday in Ibiza! It's a long journey together. So I really enjoy it."

'Edgy'

"That Christmas"—a series of entwined tales about a town of friends and relatives during a troubled festive period—is a family-friendly offering which still has a grown-up contemporary edge to it.

It features plenty of jokes and references to everything from Jesus being a hipster to abortion and climate change.

"If love were easy, your father wouldn't have run off with his 25-year-old dental nurse," one of the main animated characters, Mrs Williams, tells her schoolboy son, Danny.   

Curtis said he and co-screenwriter Peter Souter were confident the format meant they could be "modern and sometimes edgy and satirical without crossing any big red lines".

"I've always thought that you shouldn't, as it were, dumb down if you're dealing with kids," he explained.

Veteran stage and screen actress Fiona Shaw was equally enthused about contributing to a film not just aimed at adults.

"I really love a young audience, because they watch with such enthusiasm and such accuracy and such memory. They remember things," she said. 

"So I'm hoping that this audience will enjoy Ms Trapper as much as I enjoyed playing it."

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Suffolk story

Simon Otto, known for his work heading character animation for the "How to Train Your Dragon" films, makes his feature directorial debut on the project, which he said breaks new ground in the genre.

"In animation, it's very uncommon to tell multi-thread storylines—it's usually about a single hero on a fantastical journey," he explained.

"Bringing the charm and timelessness of animation to Richard's real-life stories that have universal appeal and wish-fulfilment felt like a really interesting match to everyone."

Curtis revealed that Sheeran wrote and recorded an original song for the film, "Under the Tree", largely thanks to the story's setting in the southeast English county Suffolk, where both of them live.

"Ed is, as it were, the epitome of Suffolk," the filmmaker explained, while joking the star musician's involvement could also be down to him looking "like an animated character".

"I went round, showed him the film, and he said: 'Oh, I'd love to write a song for this'. And he did it fast, and it's a really beautiful song," said Curtis. "We're really lucky."

Otto noted that the track "really became the heart of the film" as it features at a climactic moment in the movie. 

"It's building towards this moment," he said. "And he could be one of our characters."