Big Night In: Prince William, Kate Middleton and their children make surprise TV appearance to Clap For Our Carers

Family were all dressed in blue to honour the NHS

Prince William, Kate Middleton and their three children made a surprise TV appearance during the BBC’s Big night In to join the nation in applauding frontline workers during the coronavirus pandemic.

On Thursday, the Duke and Duchess of Cambridge, Prince George, Princess Charlotte and Prince Louis appeared outside Anmer Hall to take part in Clap For Our Carers.

Charlotte, four, began clapping before the rest of the family - who were all dressed in blue to honour the NHS - in the fifth week of the nationwide tribute.

Prince Charles and Camilla also appeared in the televised special and could be seen joining the clap while standing in front of their Birkhall residence in Scotland.

The applause takes places every week on Thursdays at 8pm around the country, with people standing outside their homes to show their appreciation for the incredible key workers who are keeping the country running.

The special clip aired during the Big night In, which supported Comic Relief and Children in Need.

Ahead of the 8pm clap, the duke also unexpectedly appeared in a comedy sketch with Stephen Fry, during which he admitted that homeschooling his children was “a bit of a nightmare, really”.

The family dressed in blue as they joined in with Clap For Our Carers (BBC)

Before getting up to take part in Clap For Our Carers, William said: “On my way, let me just see if I can find my socks, and my shoes, and my trousers.”

Earlier that day, William and Kate celebrated their youngest son Prince Louis' second birthday by releasing a series of photos of him painting a rainbow poster.

Prince Charles and Camilla also made an appearance during the BBC's Big Night In (Getty)

Children across the UK have been creating rainbow pictures as a symbol of hope during the coronavirus lockdown to put in their windows.

The duke and duchess also shared an informal photo that didn't make it into the official release on their Kensington Royal Twitter account.

The post featured two side-by-side photos, one which showed Prince Louis holding up his hands covered in rainbow paint and another of him spreading the colours onto his face.

“Instagram Vs Reality,” the caption read. “Thank you for your lovely messages on Prince Louis’s second birthday.”