From WENN.com

The Never Let Me Go star will lace up her running shoes to join thousands of participants in one of the Alzheimer's Society's Memory Walks, which take place throughout England, Wales and Northern Ireland this autumn (12).

The cause is close to Mulligan's heart - she became an ambassador for the organisation because her grandmother was diagnosed with the condition when she was 15.

In a public service announcement for the event, she says, ""Who will you walk with this September? Some people walk to remember a loved one. Others walk to do something great. All walk with one common goal - to fight dementia. Walk with us this September.""