Prince Harry and Meghan Markle honour Nelson Mandela

Nelson Mandela's granddaughter has described the Duke and Duchess of Sussex as a "shining example" during the royal couple's visit to a London exhibition honouring the former South African president's life.

Prince Harry and wife Meghan were guests at the opening of the Nelson Mandela Centenary Exhibition in Southbank on Tuesday.

They met multiple people, including Mandela's granddaughter Zamaswazi Dlamini-Mandela, before touring the display, which marks the centenary of the human rights activist's birth.

The Duke and Duchess of Sussex arrive for their visit to the Nelson Mandela centenary exhibition at the Southbank Centre's Queen Elizabeth Hall, London. (AAP)

The entrepreneur also praised the newlyweds for "putting their name where their mouth is" when it comes to supporting charitable causes.

During the visit, Meghan, 36, wore a sleeveless powder pink trench dress by Canadian label House of Nonie, which retails for $AUD1113 on their website.

https://twitter.com/KensingtonRoyal/status/1019194218647040001

She accessorised with a Mulberry bag and dusty pink heels. 

Meghan and Harry appeared jubilant as they waved to the cheering crowds. 

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Mandela helped bring an end to apartheid and was a global advocate for human rights. 

The exhibition provides an insight into Mandela’s journey from young freedom fighter to becoming the inspiration for an international movement against South Africa’s violent and oppressive apartheid system.

The Duchess of Sussex wears a dress by Canadian label House of Nonie. (Getty)

They met with people associated with the exhibition and with Mandela's work, including Andrew Mlangeni who stood as an accused on charges of sabotage against the then apartheid government during the Rivonia Trials in 1938.

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He also spent 26 years imprisoned on Robben Island, where Mandela famously was incarcerated for 18 years.

It's been a busy week for the Duke and Duchess, who returned from Ireland on Thursday after a two-day visit.