Singer Robbie Williams admits he is anxious about helping others, because he doesn't want to be seen as a wealthy celebrity using charity work for his own means. The star recently visited orphans in South Africa in his role as an ambassador for the United Nations Children's Fund (Unicef). As much as he loved the experience, he admits it made him uncomfortable. Williams says, "I'm an incredibly self-conscious person anyway, but it heightens where charity work is concerned. "The stigma that surrounds doing good is quite amazing and it's penetrated my psyche. "It constantly makes me question why I'm doing what I'm doing..."