The Princess of Wales is now recovering at her Windsor home following abdominal surgery and a two-week hospital stay.
The Prince of Wales has temporarily stepped back from royal duties in order to care for his wife Kate and their three children, Prince George, Princess Charlotte and Prince Louis, but no doubt the Princess' in-laws are also helping out.
King Charles shares a close bond with his "beloved" daughter-in-law Kate and he will no doubt be looking out for her as he continues his own recovery, having been treated at the same London hospital for an enlarged prostate last week.
Lady Frederick Windsor, also known as Sophie Winkleman, is married to Lord Frederick Windsor – the second cousin of King Charles.
The Peep Show star, 43, previously spoke about the King's kindness after she was seriously injured in a car crash in November 2017, suffering a broken foot and three broken bones in her back.
In an exclusive interview with HELLO! in 2018, Sophie revealed the "magnificently practical" gift from the then Prince of Wales, telling us: "Prince Charles sensed correctly that everything would be chaos at home, so he asked his cook, instead of taking care of him, to take care of us. So, our lunches and dinners were cooked at Clarence House then delivered for weeks on end while I was in hospital and then still disabled at home.
"It saved our bacon, literally, because my darling husband – well, he's good at fry-ups but that's about it. The children would have had cholesterol coming out of their ears had their diet been left to him. It was a magnificent way to help."
Charles' wife Queen Camilla has also publicly praised her husband for his thoughtfulness, telling The Telegraph in 2018: "He's incredibly kind. I don't think people see his incredible kindness and the things he does behind the scenes. People who worked for him years ago will write to him and if they've fallen on hard times he'll do everything he can to help them."
Kate, who was discharged from the London Clinic on Monday, is not expected to resume public duties until after Easter, although it is understood that her return will depend on medical advice nearer the time.
The exact details of the Princess's condition have not been revealed but Kensington Palace said previously it was not cancer-related.
LISTEN: King Charles 'loves' seeing his grandchildren Prince George, Princess Charlotte and Prince Louis