Emma Thompson, the Oscar-winning actress and screenwriter, has been a patron of homelessness prevention charity Alone in London since 1997.
Why did you become involved with Alone in London? I was appalled by the numbers of young people on London's streets and it was clear that all the money Alone in London made was invested directly into helping them.
How do you help the charity? I have visited most of its projects and spoken to young homeless people with whom I hope to do some mediation training soon. I also support and attend the charity's fundraising events.
What qualities do you bring to the charity?
I am able to drum up celebrity support as and when required. For last week's '30:30 A Vision of London' event, I contacted friends to take photos of 'their' London, which were then signed and sold to raise funds for the charity.
Do celebrities do enough to help charities? Celebrities do quite a lot, but it often seems to be the same ones. Donating money is very good, but sometimes it is used by celebrities as a way of keeping certain issues at arm's length. If your voice has a platform, it's important to raise it in support of the dispossessed and the unheard.
Do you support any other causes or organisations? I've belonged to CND, Amnesty and about 15 other organisations since I was about five, or so it seems. In response to the global Aids emergency, I visited Uganda last year and Mozambique this June for ActionAid, as what they call an "ambassador".
What I am is a communicator, a sort of piece of connective tissue between people at grass-roots level over there, and us.