Funnyman Russell Brand is calling on fans to sign up to the U.K.'s bone marrow registry to help find a match for a young fan who is battling leukaemia.

The Forgetting Sarah Marshall star met Aneesa Hussain at the Teenage Cancer Trust fundraising event in London on Wednesday (20Mar13) and the comic was so moved by the 17-year-old's plight that he encouraged his followers to get involved in her campaign.

The youngster was diagnosed with aplastic anaemia, a type of blood cancer, last year (12) and it is particularly difficult for her to find a bone marrow donor as only six per cent of those on the registry match her Asian heritage.

Brand shared a link to the teen's campaign page, writing, "My friend... Aneesa needs a bone marrow match- help us to find one... She is beautiful."