Prime Minister Boris Johnson has warned the number of COVID-19 cases in the UK is "stark" and "accelerating" as he told adults the best present they can give their mother for Mother's Day is to stay away.
A post on the Duke and Duchess of Cambridge's official Twitter page says: "To mothers new and old and families spending today together and apart - we are thinking of you all at this difficult time".
"Happy Mother's Day."
The message, which was also posted on Instagram, included pictures of the Duke and Duchess of Cambridge with their children; Diana, Princess of Wales, with Prince William and Prince Harry; Carole Middleton with her daughter Catherine; and a Mother's Day card from Prince George to his mum.
The official Instagram page of the Queen and the Royal Family also posted a poignant message, saying: "Mothering Sunday is a chance to thank and celebrate all mothers and caregivers, wherever they may be."
"Today may be a different and difficult day for those who would usually plan to spend time with their mothers, as we adapt to the necessary changes and disruption to our normal routine and regular patterns of life," it read.
"But for all Mums everywhere, we are thinking of you, and wish you all a very special #mothersday".
A 1951 photo of the Queen - then Princess Elizabeth - with her mother, Queen Elizabeth, accompanied the message.
Mr Johnson has said Britons "should really think very carefully" about seeing their mothers, saying: "It doesn't matter necessarily whether they're over 70. The issue is whether they are in one of the vulnerable groups."
Doctors have echoed this view, with GP Sarah Jarvis, tweeting that "the best present we can give elderly mums for Mother's Day is to cancel big family lunches and buy them a device with Skype or FaceTime - then use it regularly."
Planned celebrations at restaurants for lunches or afternoon teas have been cancelled after the government ordered cafes, pubs, bars and restaurants to close for the foreseeable future in the latest move aimed at halting the spread of COVID-19.
On Thursday, the Queen issued a message of solidarity, saying families around the UK were entering "a period of great concern and uncertainty".
She moved from Buckingham Palace to Windsor Castle a week earlier than planned for the Easter period - and will likely stay there longer than originally thought - with coronavirus at its most widespread in London.