Stephen Fry has lent his voice to a campaign that explores a Christmas without Santa, who has "forgotten" the festive season due to the effects of dementia.
The campaign, called Santa Forgot, has been launched by Alzheimer's Research UK (ARUK) and created by Wallace And Gromit makers Aardman Animations.
The animation follows a young girl named Freya, who on learning of Santa's condition travels to the North Pole to recruit Santa's elves as researchers, because she believes that "if Santa has a disease, research can find a way to fix it".
New figures released by the Office for National Statistics (ONS) show that dementia and Alzheimer's disease have become the leading cause of death in England and Wales for the first time.
Stephen said: "From the moment I was told about Santa Forgot I wanted to lend my support - it is an inspiring and beautiful take on a Christmas tale.
"I urge people up and down the country to get behind the campaign so we can fuel the fight against dementia and take a step forward to making it history."
According to the NHS, around 850,000 people in the UK are affected by dementia, while the recent ONS statistics show that the mortality rate for dementia and Alzheimer's has more than doubled over the last five years.
Liz Ayre, a Alzheimer's Research UK champion, lost her husband Mike to early-onset Alzheimer's in 2013 and their daughter, Ciana, voices Freya in the animation.
Liz said: "Santa Forgot is beautiful, sad and hopeful all at once and stirred so many different emotions when we watched it. The film shows that dementia doesn't discriminate: It affects people from so many different backgrounds, from nurses and teachers to world leaders and eloquent writers.
"I hope Santa Forgot gives people two minutes to think about the impact of dementia this Christmas, and be inspired by how we can change the future with research.
"I'm proud that my family has been involved in the campaign, and to hear Ciana bring Freya's voice to life in the animation is a special moment for us and a great tribute to Mike."
Chief executive of Alzheimer's Research UK, Hilary Evans, said the campaign is a "poignant and powerful reminder that dementia doesn't discriminate".
She said: "We have to be provocative about dementia, to help fight misconceptions and fatalism around the condition and to demonstrate that pioneering research holds the answers.
"Santa is an important cultural figure, but the idea that he too could be affected drives home the point that dementia can strike those most special in our lives."
She added that the campaign "reminds us to believe in the power of research".