After the statesman's sad passing last week, the Prince described him as the "embodiment of courage and reconciliation".
"He was also a man of great humour and had a real zest for life," Charles said.
"With his passing, there will be an immense void, not only in his family's life, but also in those of all South Africans and the many others whose lives have been changed through his fight for peace, justice and freedom."
Michelle Obama meeting the elder statesman in 2011
On Tuesday, US President Barack Obama, Michelle Obama and UK PM David Cameron will be among those attending a memorial service at a Soweto stadium.
World leaders, global figures and celebrities will join 95,000 ordinary South Africans at the event at FNB stadium in Soweto, where Mr Mandela made his last major public appearance during the 2010 football World Cup.
Three former US presidents, George W Bush, Bill Clinton and Jimmy Carter, will also attend.
State funeral will take place on 15 December
Following the ceremony, Mr Mandela's body will lie in state in Pretoria for three days before his state funeral on Sunday, 15 December.
A smaller number of international dignitaries, including Prince Charles, will attend the burial in the Eastern Cape village of Qunu, where the late president grew up.