Celebrities can make a real contribution to ending world hunger, former UN secretary general Kofi Annan said today.

The campaigner claimed stars who use their fame and popularity to help the needy can make a difference to global poverty.

``They do make a contribution but one has to know how effectively to work with them and to use them,'' said Mr Annan, at an international conference on fighting hunger in Dublin.

``They have a voice, they have visibility, they are very good in delivering messages in their training.

``And if take a message and use their popularity and fame to help the needy, and working whether with Concern or the UN or whoever, it can be very helpful - but provided all are agreed on the objective and one stays on the message.

``My good friend Bono, he is an outstanding spokesperson for the fight against poverty and has gone on to work with others and has gone out of his way to raise funds for it.''

But Mr Annan said he was shocked when he once saw a Unicef ambassador promoting soap on television and he called the charity to complain.

``She came in to help Unicef and help the poor, not to exploit the image of Unicef to sell soap,'' he added.

Mr Annan also told how he was once mistaken for Hollywood star Morgan Freeman.

He said when he stepped down as secretary general he and his wife took a three-month break with no radio, television or newspapers.

``After six weeks I began to get bored so I said let's get a newspaper,'' he said.

``We walked in to a tobacco shop and within three minutes I saw a group of men gather looking in our direction and one of them broke away and made straight in my direction.

``So I said to my wife, 'gosh we've blown our cover and we still have six weeks to go, how arewe going to manage?'

``The man came straight up to me and said 'Morgan Freeman can I have an autograph?' I said sure, so I signed M Freeman.

``He was happy and I was happy.''