The Duke of Cambridge, who is expecting his third child with Kate Middleton, was introduced to the popular chicken restaurant chain by one of his Met Police protection officers.
The prince joins the likes of Jay-Z, David Beckham and Rihanna, who are also said to enjoy the spicy peri peri chicken on offer at the restaurants.
William made the revelation at a joint Commonwealth Business and Youth forums event at the Queen Elizabeth II conference centre in London.
Business leaders and philanthropists from across the world gathered to share their advice with young entrepreneurs.
William was introduced to the co-founder of Nando’s Robert Brozin, and pointed out his security officer before telling him: “This man here is your biggest fan.
“He introduced me to Nando’s, it’s very good, he should buy a stake in Nando’s.”
The prince later gave a brief speech in which he told of his admiration for the entrepreneurs he meets on his trips overseas.
He said: “As I have travelled across the Commonwealth and here in the UK, I have always been impressed by the ingenuity, the drive and commitment of those I meet behind small and medium-sized companies particularly.
“When Catherine and I visited India in 2016, we were completely blown away by the innovation on display in the Indian businesses we met from Formula E-Cars and new ways of teaching braille.”
William also spoke about his ambitions for the Royal Foundation which he founded with Prince Harry and Kate in 2011, and which Meghan Markle will join as its fourth patron after the Royal wedding.
He told delegates: “We, as the Royal Foundation, can help lead, but if we can connect to some of those bigger foundations in the world and come together with one message, imagine the focus and the change.
“I like the idea of a team. Its all about how we work together.”
Mr Brozin, who opened his first restaurant in South Africa in 1987, said about William: “I’m not surprised he’s eaten at Nando’s.
“The beauty of Prince Harry and Prince William is that they’re really accessible and they are guys that go out a lot – I’m very happy that they’ve tried it.
“I was certain they would have tried it because they’re so accessible.
“They’re people’s people, which is so nice.”
The Duchess of Cambridge is returning to the Lindo Wing of St Mary’s Hospital in Paddington to have her third child.
In October the palace revealed Kate Middleton is due to have her third child in April, but a more specific date has not been revealed.