Celebrity promotion of charities is ineffective at raising awareness but can make the stars more popular with the public, a study says.
A survey of more than 2,000 people found two thirds could not link any celebrity with a list of seven well-known charities and aid organisations that they worked for.
Stars did not support charities for self promotion, but this was the unintended outcome of their work, researchers concluded.
The seven organisations mentioned in the survey were Action Aid, Amnesty International, CAFOD, Christian Aid, Oxfam, Save the Children and the Red Cross.
Speaking about their study which also used focus groups, Professor Dan Brockington, of the University of Manchester, and Professor Spencer Henson, of the University of Sussex, said: "Our survey found that while awareness of major NGOs (non-governmental organisations) brands was high, awareness of celebrity advocates for those brands was low.
"Instead it was plain from the focus groups that most people supported the charities that they supported because of personal connections in their lives and families which made these causes important, not because of the celebrities.
"The evidence suggests therefore that the ability of celebrity advocacy to reach people is limited and dominated in Britain by some extremely prominent telethons and the work of a few stars.
"Regardless of what celebrities may want in terms of publicity - and the interviews suggest that many would seek to maximise the attention given to their cause and not to them - it is clear that the celebrity can often do better out of this attention than their causes."
In a separate related study, also published online in the International Journal of Cultural Studies, Dr Martin Scott, of the University of East Anglia, conducted focus group observations with 108 people with nearly half asked to keep a diary on their thoughts about poorer countries.
Dr Scott said: "In the diaries only 6% of all entries were about celebrity humanitarianism - almost all of which were about programmes or advertisements in the build-up to Comic Relief.
"Celebrities were both valued for their seemingly instrumental role in drawing attention to worthy causes but at the same time this was often accompanied by cynical statements (written in the diaries) about their motivations for involvement or about the genuineness of their emotional responses.
"There were still a relatively large number of occasions in which seemingly authentic celebrities did appear to generate a distinct sense of proximity and agency vis-a-vis distant suffering.
"However, overall the results of this research suggest that celebrities are generally ineffective in cultivating a cosmopolitan engagement with distant suffering. In conversations about the mediation of distant others, research participants rarely talked about instances of explicit celebrity humanitarianism."