CBBC star Doc Brown pays tribute to Mandela
6 December 2013 Last updated at 10:46 GMT
Nelson Mandela, one of the world's greatest leaders, has died aged 95 after a long illness.
Mandela led South Africa out of the racist system of apartheid, and into democracy, becoming the country's first black president.
4 O'Clock Club star Doc Brown told Newsround why he thinks Nelson Mandela was so important.