Carey Mulligan has said she feels "privileged" to be able to raise awareness for certain causes due to her level of stardom, despite leading a largely private life.
The Academy Award-nominated actress was the guest editor on BBC Radio 4's Today programme, on which she campaigned to change the public's perception of dementia and also discussed her work with the charity War Child.
Mulligan, 31, is an ambassador for both the Alzheimer's Society and War Child, which aids children in areas of conflict.
She told radio hosts Nick Robinson and Justin Webb that she felt "lucky" to be able to do what she does to speak out for these charities, although she favoured keeping her personal life private.
She said: "I've been so lucky that I've been able to work over the last 10 years and I get to do the jobs I want to do, and I certainly don't enjoy anything sort of invasive but I do feel really privileged to represent these organisations in some small way."
Asked if she minded bringing herself more into the public eye for charitable causes, she said that there was "definitely a crossover, particularly with dementia and War Child" in that the issues were "personal and emotional".
She said that people may see her in movies and are therefore perhaps more likely to listen to what she has to say about these causes, but that she was not the real "expert".
Mulligan said: "I'm never the expert in these situations.
"The lucky thing I have is that people have seen a couple films, maybe they'll listen to something they might not ordinarily listen to if I do an interview on TV about Alzheimer's, so that's a great privilege."
In November, Mulligan added her voice to calls from War Child for Prime Minister Theresa May to take action against those responsible for the suffering of a quarter of a million civilians believed to be trapped in eastern Aleppo.
And she has also extensively supported the Alzheimer's Society after seeing the impact dementia can have, following her own grandmother's diagnosis 12 years ago.
On the current affairs programme, Mulligan continued her fight to raise awareness of the disease and urged people to stop treating it as a joke.
Mulligan said: "It gets tiresome hearing dementia being the butt of a joke.
"I think there's a general misunderstanding in a lot of areas that dementia is a natural part of ageing, or it's just something that happens to you when you get older.
"I used to grow up hearing a lot of people saying about their grandparents having 'lost their marbles', which is of course something we'd never say about someone who had cancer or heart disease.
"I think the understanding that dementia is a disease - it's a disease of the brain - there are lots of different kinds of dementia and Alzheimer's is one of them, and just spreading that awareness so that people really understand that this is a disease we have to fight."
She also sat down for a pre-recorded discussion with TV's Michael Parkinson and Michael Palin, both of whom have, or have been close to people with the disease.
Parkinson saw his mother go through dementia before her death, and Palin's Monty Python co-star Terry Jones has been diagnosed with primary progressive aphasia, which will impact his capacity to communicate.
Mulligan explained how her grandmother, whom she calls "Nans", responds to music due to its "nostalgic" qualities, and Palin said that "chimes with the way Terry spends a lot of his time now".
Palin said: "He watches old musicals, and not just musicals of 10 years ago, 20 years ago - musicals of the 30s and 20s, so there's that nostalgia there.
"He loves watching those, he'll watch them time and again and I find that incredibly touching."