King Charles and the Princess of Wales have developed a very special bond over the years, which has only strengthened since he described her as his "darling daughter-in-law".
The pair have stepped out on numerous royal engagements together, giving an insight into their relationship through private jokes and affectionate cheek kisses.
" Kate and Charles do seem to have a rather special relationship that shows up visibly in public as the pair seem to single each other out for attention and empathetic signalling," behavioural expert Judi James told the Express.
"Their body language together suggests they are tuned in to each other, using flattery and mirroring signals to show some like-minded thinking or appreciation of a joke."
And to make sure she has the support she needs on the day of his Coronation, Charles has made a kind gesture on Kate's behalf - inviting her family to the celebrations.
Here we look back at how they developed their bond and now enjoy being in each other's company...
First meeting
Kate and William started dating while they were students at St Andrews University in Scotland.
And it appears even in those early days and before the pair announced their engagement in 2010, Charles welcomed his would-be daughter-in-law into the family with open arms.
In an interview to mark their engagement, Kate said Charles had been "very, very welcoming" and "very friendly".
She admitted that she was nervous to meet her future father-in-law but added: "It couldn't have gone easier, really for me."
Wedding speech
In 2011, proud dad Charles was overcome watching his eldest son tie the knot and gave a tear-jerking off-the-cuff speech about the couple during a champagne reception at Buckingham Palace.
He is said to have described Kate as like the daughter he never had and said: "We are lucky to have her."
He then wished the couple a lifetime of happiness together.
Since the lavish ceremony, their bond has only strengthened.
Cheeky private jokes
Kate and Charles are often spotted sharing private jokes while out and about on public engagements.
Last year, in a visit to a veterans rehabilitation centre in Loughborough, Kate was pictured in fits of giggles as she stood next to her father-in-law.
William and Camilla were also there on the visit, and body language expert Judi James told the Express that by wrinkling her nose, Kate's laugh showed "genuine humour and rapport".
She added: "The affection Kate clearly feels for her father-in-law could be one big thing she has in common with Camilla."
Helped to smooth over Charles and William's bond
Despite Kate and the King's sweet relationship, the bond between Charles and William is said to have been rocky in the past.
According to reports, it was Kate herself who helped to smooth things over between her husband and father-in-law.
And she did this by reportedly helping to organised a family portrait for Charles for his 70th birthday in 2018.
She also snapped a symbolic photo of Charles and his eldest son on William's birthday, in which the dad can be seen resting his head on her husband's shoulder.
Endearing nickname
Kate appears to have an endearing nickname for her father-in-law.
During a meeting at the G7 summit in 2021, the Princess referred to Charles as "grandpa", according to a lipreader.
The royals were attending a drinks reception with some of the world's leaders, who were in Cornwall for the political summit.
And it appeared that, upon arrival, Kate said to Charles: "Hello Grandpa, how are you?"
The future king of England is grandfather to Kate and William's three children, George, Charlotte and Louis.
Sweet gestures
Not only are Kate's beloved parents Carole and Michael on the Coronation invite list this weekend, but the King has also invited her sister Pippa and brother James.
He is said to have noted how Pippa "made such an impact" at the wedding of her sister to Prince William 13 years ago that it was important she felt a part of the celebrations again.
"They are the family of our future queen, so it's right that they should be there," added source to the Daily Mail.
Carole and Michael enjoyed the Queen's Platinum Jubilee Party last June, before paying their respects at the funeral and committal service in September.
