Nelson Mandela's widow Graca Machel listens as South Africa's President Cyril Ramaphosa speaks from the balcony where Nelson Mandela gave his first speech after his release from prison 30 years ago, in Cape Town, South Africa, February 11, 2020. REUTERS/Sumaya Hisham

Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, arrive before meeting Graca Machel, the widow of the late Nelson Mandela, at the British High Commissioner's residence, Johannesburg, South Africa, October 2, 2019.REUTERS/Siphiwe Sibeko

A woman records a video as Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, arrive to deliver a statement before meeting Graca Machel, the widow of the late Nelson Mandela, at the British High Commissioner's residence, Johannesburg, South Africa, October 2, 2019.REUTERS/Siphiwe Sibeko

Britain's Prince Harry delivers a statement before meeting Graca Machel, the widow of the late Nelson Mandela, at the British High Commissioner's residence, Johannesburg, South Africa, October 2, 2019.REUTERS/Siphiwe Sibeko

Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, arrive to deliver a statement before meeting Graca Machel, the widow of the late Nelson Mandela, at the British High Commissioner's residence, Johannesburg, South Africa, October 2, 2019.REUTERS/Siphiwe Sibeko

Meghan, Duchess of Sussex, speaks with Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Meghan, Duchess of Sussex, attends a meeting with Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, arrive to meet Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, meet Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Meghan, Duchess of Sussex, attends a meeting with Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, meet Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, meet Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, meet Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, meet Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Meghan, Duchess of Sussex, smiles as she arrives to meet Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Meghan, Duchess of Sussex, smiles as she arrives to meet Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Meghan, Duchess of Sussex, walks with Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, meet Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, meet Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, meet Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Meghan, Duchess of Sussex, walks with Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Meghan, Duchess of Sussex, walks with Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Meghan, Duchess of Sussex, walks with Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, meet Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Meghan, Duchess of Sussex, shakes hands with Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, meet Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Britain's Prince Harry, the Duke of Sussex, greets Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, meet Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, meet Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Meghan, Duchess of Sussex, shakes hands with Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Meghan, Duchess of Sussex, shakes hands with Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, meet Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Meghan, Duchess of Sussex, shakes hands with Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, meet Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, meet Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Meghan, Duchess of Sussex, speaks with Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, meet Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, meet Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, meet Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool TPX IMAGES OF THE DAY

Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, meet Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, meet Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Graca Machel, the widow of the late Nelson Mandela, waits to greet Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Graca Machel, the widow of the late Nelson Mandela, waits to greet Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Graca Machel, the widow of the late Nelson Mandela, waits to greet Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, meet Graca Machel, the widow of the late Nelson Mandela, in Johannesburg, South Africa, October 2, 2019. REUTERS/Chris Jackson/Pool

Graca Machel, member of the Elders speaks at the Nelson Mandela Peace Summit during the 73rd United Nations General Assembly in New York, U.S., September 24, 2018. REUTERS/Lucas Jackson

Graca Machel, member of the Elders speaks at the Nelson Mandela Peace Summit during the 73rd United Nations General Assembly in New York, U.S., September 24, 2018. REUTERS/Lucas Jackson

Graca Machel, member of the Elders speaks at the Nelson Mandela Peace Summit during the 73rd United Nations General Assembly in New York, U.S., September 24, 2018. REUTERS/Carlo Allegri

Graca Machel, member of the Elders speaks at the Nelson Mandela Peace Summit during the 73rd United Nations General Assembly in New York, U.S., September 24, 2018. REUTERS/Lucas Jackson

Former U.S. President Barack Obama is embraced by Nelson Mandela's widow Graca Machel after he to delivered the 16th Nelson Mandela annual lecture in Johannesburg, South Africa July 17, 2018. REUTERS/Siphiwe Sibeko

Nelson Mandela's widow Graca Machel addresses crowds gathered to hear former U.S. President Barack Obama delivering the 16th Nelson Mandela annual lecture in Johannesburg, South Africa July 17, 2018. REUTERS/Siphiwe Sibeko

Former U.S. President Barack Obama greets Nelson Mandela's widow Graca Machel as he arrives to deliver the 16th Nelson Mandela annual lecture in Johannesburg, South Africa July 17, 2018. REUTERS/Siphiwe Sibeko

Nelson Mandela's widow Graca Machel waves to the crowds gathered to hear former U.S. President Barack Obama delivering the 16th Nelson Mandela annual lecture in Johannesburg, South Africa July 17, 2018. REUTERS/Siphiwe Sibeko

Former U.S. President Barack Obama greets Nelson Mandela's widow Graca Machel as he arrives to deliver the 16th Nelson Mandela annual lecture in Johannesburg, South Africa July 17, 2018. REUTERS/Siphiwe Sibeko

Graca Machel, widow of former South African President Nelson Mandela arrives at the Orlando stadium before the funeral of Winnie Madikizela-Mandela in Soweto, South Africa April 14, 2018. REUTERS/Siphiwe Sibeko

Graca Machel, widow of former South African President Nelson Mandela arrives at the home of late Winnie Madikizela-Mandela before the funeral in Soweto, South Africa April 14, 2018. REUTERS/Rogan Ward

Graca Machel, widow of former President Nelson Mandela attends a memorial service for Winnie Madikizela-Mandela at Orlando Stadium in Johannesburg's Soweto township, South Africa April 11, 2018. REUTERS/Siphiwe Sibeko

Graca Machel, widow of former President Nelson Mandela attends a memorial service for Winnie Madikizela-Mandela at Orlando Stadium in Johannesburg's Soweto township, South Africa April 11, 2018. REUTERS/Siphiwe Sibeko

Former Irish President Mary Robinson joins Finland's former President Martti Ahtisaari and Graca Machel, widow of former President Nelson Mandela on a walk to commemorate what would have been Mandela's 99th birthday in Cape Town, South Africa, July 18, 2017. REUTERS/Mike Hutchings

Former Irish President Mary Robinson and Graca Machel, widow of former President Nelson Mandela, join a walk to commemorate what would have been Mandela's 99th birthday in Cape Town, South Africa, July 18, 2017. REUTERS/Mike Hutchings