Prince William and Duchess Catherine broke with Royal tradition during their recent appearance on 'Blue Peter.

Prince William and Duchess Catherine

Prince William and Duchess Catherine

The duo put on an unusually affectionate display during their time on the popular BBC show, with the Duchess seen touching her husband's knee as they chatted with the presenters.

Their appearance has even been compared to the recent behaviour of Prince Harry's wife-to-be Meghan Markle, who staged a loved-up interview with the royal after announcing their engagement.

Prince William and the Duchess - who have Prince George, four, Princess Charlotte, two, and are expecting their third child - appeared on the show to collect their Gold Blue Peter badges.

The duo were given the accolade for their work with mental health and how mental health issues affect children, following in the footsteps of Queen Elizabeth, who was given a badge back in 2002.

Prince William said: "That's very touching. Thank you very, very much. Wow, that's amazing ... We have won a badge!"

Before adding about their work with mental health: "We've still got a long way to go yet but we are getting there. A shift is happening and we will hopefully crack a problem that should have been cracked a long time ago."

The Duchess also admitted to being honoured to have been handed one of the coveted badges.

She said: "It's hugely special. Mental health has been a learning process for us too ... We want to get everyone talking about it so it hasn't got that stigma it's had."