During the call with staff, The Duke of Cambridge said: "We'd just like to say from the two of us how proud we are of all of you and how amazingly you are all doing under extreme circumstances. I know all of you see this as your job and that you get on with it, but this is a different level and you are doing an incredible job.
"The whole country is proud of you so thank you for everything you're doing and all the hours you are putting in."
The family, including their children, Prince George, Princess Charlotte and Prince Louis, are currently self-isolating at Anmer Hall in Norfolk, as the UK battles the coronavirus pandemic.
While the Cambridge clan usually live at Kensington Palace, they have decamped to the country for lockdown, and given royal fans a glimpse inside their 10-bedroom Sandringham Estate home.
The sneak peek came as they announced they were launching a £5million ($10m) scheme to support the UK people's mental health at a time of high anxiety during the lockdown.
The Duke and Duchess of Cambridge shared two photos of themselves with their 11.5m Instagram followers on Saturday.
Kate was seen wearing a dusky pink suit at a desk, while talking on the telephone to one of her patronages.
William was also on the phone in his snap, at another desk, to one of the organisations and patronages he supports.
"Self-isolation and social distancing can pose huge challenges to our mental health — in recent weeks The Duke and Duchess of Cambridge have been in regular contact with organisations and patronages to understand the issues they are facing during this difficult time," they captioned the photos.
"Today Public Health England has published new guidance to help support people during the COVID-19 outbreak, and updated its world-leading Every Mind Matters platform, with specific advice on maintaining good mental wellbeing during the outbreak; take a look at our Story or visit the link in our bio 📱 to find out more.
Speaking about the new guidance, The Duke and Duchess said: “It is great to see the mental health sector working together with the NHS to help people keep on top of their mental well-being.
By pulling together and taking simple steps each day, we can all be better prepared for the times ahead.”
Last week the Cambridge kids came together to join a UK nationwide initiative to thank health workers.
Prince George, Princess Charlotte and Prince Louis joined millions of people across the UK in clapping for NHS workers on the frontline in the battle against the coronavirus pandemic.
WATCH: Prince George, Charlotte and Louis applaud COVID-19 health workers