As we hurtle towards Mariah Carey's most lucrative holiday, families all over the UK will be pressing play on Christmas films such as Love Actually to get themselves into the festive spirit.

The 2003 movie was one of a string of hits from writer-director Richard Curtis which dominated the box office at the turn of the millennium, alongside Notting Hill, Bridget Jones's Diary and Four Weddings and a Funeral.

Curtis is returning to the Christmas theme for his latest film, but this time around he has moved away from the traditional romcom and taken on his first animated project.

"The thing for me is, it's been a long time since I was, as it were, on the dating market," he tells BBC News. "But I've been a dad for the last 25 years, so it was a real joy for me to be able to write about kids."

The film-maker has described working on animation as "a huge treat and revelation for me", adding that the "whole process is so different from the other movies I’ve worked on".

That Christmas, released on Netflix on 4 December, is adapted from the book of short stories Curtis published in 2021.

Set in the fictional coastal town of Wellington-on-Sea, the film follows a handful of families gearing up for Christmas Day. When a blizzard hits the town and leaves the parents separated from the children, their carefully planned celebrations are thrown into chaos.

The theme of Christmas gone wrong was highly relatable to Swiss director Simon Otto, who has previously worked as an animator on How to Train Your Dragon and Enchanted.

"I know from my own family growing up, we had such a clear idea of the timeline of how Christmas or any tradition will unfold," he tells BBC News.

"And I can count more times where it didn't happen the way you expect and somehow something got messed up.

"We all have a Christmas memory where something goes wrong, those are the Christmases you remember the most, and at the end of that experience you always feel like, 'My god, we were able to be together for this time, and the realisation that that's what it's really all about."

He adds: "I thought there was a beautiful poetry in that which we really wanted to bring out in the film, and make it as familiar to people as we can, but also contemporary and real."

The 90-minute film features the voices of Curtis regulars such as Bill Nighy, alongside Fiona Shaw, Jodie Whittaker, Lolly Adefope and Brian Cox as Santa Claus.

That Christmas premiered at the London Film Festival in October, where it received broadly positive reviews from critics.

"It can be easy to sneer at the arrival of a new Christmas movie," noted the Hollywood Reporter's Lovia Gyarkye.

"Genuine holiday cheer is tough to conjure and, if you’re not the intended audience for Hallmark-type saccharinity, the festive fare likely inspires more exasperation than joy.

"But this one slyly avoids the usual mawkishness by grounding its whimsical story in the real and prickly emotions of life."

Next Best Picture's Philip Bagnall suggested the film is "engineered to keep the kids busy around 4pm on Christmas Day while mum and dad sip their third Irish coffee in peace".

"This is unlikely to become a festive classic," cautioned Screen Daily's Wendy Ide. "But the message is a persuasive one: that Christmas comes in many shapes and forms and, ultimately, the only holiday tradition that is non-negotiable is goodwill to all."

The film sees the children of the town left to fend for themselves, providing an opportunity to design the kind of Christmas Day they dreamed of, rather than the one planned by their parents which observed various family traditions.

In one scene, the kids attempt to watch a Christmas film as their parents had suggested, but they get so bored they turn it off within moments. In a cheeky twist, the film they dismiss is Curtis's own Love Actually.

Otto says he planted this joke in the movie without Curtis knowing. When the writer finally saw it, he jokes he found it "very hurtful".

"No, not really," he laughs. "It reminded me of course that, when you say 'boring old Christmas movie', I think of Miracle on 34th Street or whatever, but when you say it to a young person, they say Love Actually. It was 20 years ago!"

One of the film's central questions is whether families should stick to traditions or be open to new experiences.

"The truth is that it shouldn't be all traditions nor a complete reinvention," Otto reflects, "because some traditions are there for a reason, and we love them. We talk about Santa to our kids for a reason, because there's something magical."

One striking thing about the film is how contemporary and diverse it feels. Curtis's earlier films were made in a different era, and he has said in recent years his approach to casting would be different today.

But That Christmas does its best to make up for lost ground. As Ide noted in her review, the film "unfolds in a fictional Suffolk seaside town... but the wide mix of accents and ethnicities suggests that the filmmakers have tried to cram the whole of Great Britain into this single tiny village".

It's not only the mixed-race family at the centre of the film which make it feel of the times. The children in the movie are concerned about climate change, and one has chronic anxiety.

There are lighter modern flourishes too - the father in one family christens his van Beyoncé, smartphones play a big part in the plot, and the soundtrack features Dua Lipa and Ed Sheeran.

Curtis acknowledges the conscious effort to make the film feel current. "I started my career on a show called Not The Nine O'Clock News," he recalls, "which was contemporary sketches, and I think always in my films I've tried to write jokes that make me laugh now, rather than traditional jokes.

"And the thing about being a parent is you spend most of your life in the real world of your kids, so I love the fact that it does feel modern, because life as it comes at you these days just is modern."

Otto picks up: "It felt true to me. If you take a snapshot of who lives [in the UK], it varies from region to region of course, but it's such a diverse, interesting, eclectic mix of people.

"It feels to me like that's the world we live in, and certainly we didn't want to create a world we lived in 10 years ago. If anything, we wanted to create a world we might live in 10 years from now, so more forward looking."

The film is being released in a healthy year for animation, with The Wild Robot, Inside Out 2 and Flow among those competing in this year's awards race.

But there is still a certain snobbery towards animated films, and only three have ever scored a best picture nomination - Beauty and the Beast, Toy Story 3 and Up.

Director Guillermo del Toro has previously championed it as its own craft, commenting: "Animation is not a genre for kids. It's a medium for art."

Curtis agrees: "I feel quite strongly about that at this moment, because for me, the two Spider-Verse movies are the most remarkable movies of the last 10 years.

"I watch them and I think, 'they must have taken 300 years to make, they're so extraordinary'. In the same way it's turned out that much pop music, which used to be looked down on, is really great, I think every genre can be great, and there are some amazing works of art in the world of animation."