Kate Middleton and Prince William make sweet surprise TV appearance with their children

Kate Middleton and Prince William are sharing the love and showing their appreciation for all the medical workers on the front lines in the battle against Covid-19 with their children Prince George, Princess Charlotte and Prince Louis.

Surprising BBC One's Big Night In viewers, the Cambridges joined millions of people up and down the UK, as they applauded all the heroes working at the National Health Service (NHS).

Taking to social media, the Duke and Duchess of Cambridge shared the sweet video of their rare appearance.

Alongside the Instagram video, the couple wrote: "This evening The Duke and Duchess of Cambridge, Prince George, Princess Charlotte and Prince Louis joined the UK in the weekly #ClapForOurCarers to show their appreciation for the incredible key workers working tirelessly to keep the country running.

"Ahead of the 8pm clap The Duke joined #Blackadder’s General Melchett (aka @StephenFryactually) for some video call fun on the @BBC’s Big Night In.

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"#TheBigNightIn celebrated the acts of kindness, humour and the spirit of hope and resilience that is keeping the UK going during the COVID-19 Pandemic — visit @ComicRelief to find out more."

The family's display of gratitude comes after Clarence House announced that Prince Charles had previously tested positive for the virus.

The "Clap for our Carers" campaign, a UK nationwide initiative to show thanks and appreciation for NHS workers during this unprecedented time.