Actress Carey Mulligan talks about her grandmother's Alzheimer's
21 May 2012 Last updated at 00:58 BST
Carey Mulligan's grandmother, known as Nans, was diagnosed with Alzheimer's eight years ago.
The actress has now become an ambassador for the Alzheimer's Society.
Here, she tells the BBC's Adam Brimelow about how she first became aware of her grandmother's condition in her teens and talks about how it has affected both her grandmother and her family.