Mog, the illustrated pet whose stories have been read by children since 1970, is animated on screen in the three-minute advert, produced by the same company that made the Paddington bear movie.
Judith Kerr, the 92-year-old author of the Mog stories who has written a new book for the campaign, even makes a cameo in the feel-good clip, which will raise money to support child literacy.
Kerr, who also wrote The Tiger Who Came To Tea, has written and illustrated the new book - her first since 2002 - called Mog's Christmas Calamity.
Mog's reappearance may be a surprise to some, given that she died in the last Mog book in 2002. In 'Goodbye Mog', the cat went to heaven, in a groundbreaking move for children's literature that aimed to teach kids about loss.
Publisher Harper Collins told The Huffington Post UK that the books - including Mog and the Baby, Mog in the Dark and Mog's Amazing Birthday Caper - are not in chronological order.
In the advert, the accident-prone pet is faced with a series of unfortunate events where the kitchen catches fire on Christmas eve. She manages to call the fire brigade and save the house - but not the presents and the meal.
Mog's owners, the Thomas family, are devastated, but the celebrations are salvaged thanks to their neighbours, who visit and share their food, drinks and decorations.
Kerr - who was awarded an OBE for her work and told a fictionalised version of her childhood escape from Nazi Germany in When Hitler Stole Pink Rabbit - called the advert "A wonderful extension of my little books".
She appears as a neighbour visiting the family in their snowy front garden, saying of her cameo: "I was a bit worried because we had to do it six times. But it was the cat. The cat wasn't looking in the right direction."
Kerr's new book tells a similar story to the advert and will be on sale for £3 in Sainsbury's shops. At least £2 from each book sale will go to Save The Children, which the supermarket has partnered with for the campaign.
Profits from the book and a £10 Mog soft toy will go to Save the Children's work with child literacy across the UK. The charity says that every year, one in five children in England leave primary school unable to read well, with dramatic effects on their futures.
The advert was created by ad ad agency Abbott Mead Vickers BBDO, and produced by FrameStore, the production company that worked on the Paddington bear movie.
Though the actors and sets in the advert are real, plain white model cats and soft toys were used in filming to stand in for the animated Mog, who was added in post-production.
Sainsbury's Christmas offering in 2014 was a First World War themed advert based around the Christmas Day football match that took place between enemy British and German soldiers outside the trenches in December 1914.
The Mog campaign will support Save the Children’s work with child literacy around the UK, funding programmes working directly with children, as well as supporting the charity's workas part of the Read On. Get On. coalition which aims to tackle the "reading crisis" among British children.
Tanya Steele, Executive Director of Marketing, Fundraising and Communications at Save the Children said: “We are delighted to be a part of this year’s Christmas campaign for Sainsbury’s and so grateful for the spotlight that it places on the issue of child literacy in the UK. We want reading, which is the key to a child’s future, to become a national mission.
"We are calling for everyone from parents to grandparents, communities and schools to business and government to get all children reading well by the age of eleven.
"Thanks to the support of everyone involved in this campaign, we will be able to give more UK children - particularly those children from the poorest families - the essential early language skills they need to succeed in life.”