As the star of Doctor Who, Christopher Eccleston regularly faced down villains. However, his new foe is the toughest one yet.

The actor fronts a campaign for Alzheimer’s Research UK. It’s all about an orange, for reasons that will become startlingly clear once you’ve watched it.

“Like many of you, I’ve witnessed the devastating effects of dementia,” Eccleston explains. “But because many people think dementia is just a natural part of aging, they don’t realise that it’s something that we could one day defeat.”

The first step is to raise awareness of the disease, and that’s where you come in. Watch the movie then share it with the hashtag #sharetheorange, and you could help stop a cruel disease in its tracks.