Carey Mulligan's caring role
15 August 2013 Last updated at 11:27 BST
Actress Carey Mulligan is ditching her glamorous Great Gatsby gowns and putting on a pair of walking boots for her latest role.
The BAFTA winner is an ambassador for The Alzheimer's Society and is taking part in one of the charity's Memory Walks this September.
The actress told BBC Breakfast that she got involved with the charity after her grandmother Margaret, known as Nans, was diagnosed with the condition 12 years ago.
Nans is now living at a care home in Pontardawe, near Swansea.
The Alzheimer Society's Memory Walks are taking place in England, Wales and Northern Ireland throughout September.