And now a body language expert has analysed the scene to decode the family dynamic.
“By proposing on what looks like the top of the world it looks as though Rio was determined to create a romantic fairy-tale moment and memory for his three girls as well as Kate,” Judi James exclusively told Mirror Online.
“He’s in full movie-hero mode here with one hand pushed into his pocket while Kate snakes an arms around his neck and the pair look deeply into one another’s eyes.
“It’s such an inclusive moment too though, with the girls watching with their hands clapped to their mouths with excitement.
“All children love to believe in a happy ending and that’s very much what Rio has presented for them here.
“His focus is so cleverly shared between Kate and the girls, and a scene that could have come out of a Disney movie quickly turns into a group hug with Rio combining the roles of romantic lead and doting dad as he places an arm around his daughters’ shoulders and looks down at them smiling to enjoy their reaction to the proposal.
“With this tender family sharing in mind Rio’s showing he and Kate will be together forever, while Kate’s gaze of love for him in both fiancé and father roles endorses that message.
“The perfect end to our holiday … How could the answer not be yes,” she captioned the adorable snaps.
The family had been holidaying in Abu Dhabi and Rio asked Kate to be his wife on the rooftop of the luxurious St. Regis Hotel.
Sweetly, proud dad Rio made sure to include his kids in his proposal after Kate became their full-time stepmother, following the death of their own mum.
He revealed on his own Instagram that the children had managed to keep the special moment a secret from Kate, joking that he’ll “never know” how they did it.
Rio and Kate sparked engagement rumours earlier this summer when Kate was snapped ‘hiding’ her left hand.
Marriage hasn’t been far from their minds for some time, it seems.
“We do talk about it,” Rio recently told the Daily Star, “but I’m not going to sit here and give you a date.”
Rio’s kids, who he had with his late wife Rebecca Ellison, will approve of their marriage too.
“My relationship with Kate has helped in that they have got a female in the house now,” he told The Times Magazine earlier this year.
“They run past me sometimes to go to her. I’ve had to go through a period of being very, very open, and men aren’t normally like that naturally.
“So having that extra person in the house who is female, who has that softer touch, I think is vitally important for the kids.”
And with their impending wedding on the horizon, Kate and Rio have also dropped hints they’re considering expanding their blended family.
“The kids would like a little brother or sister; they say ‘I dreamt that you were pregnant’,” she admitted to Mail on Sunday’s You magazine in August.
“But right now we’re just happy with our little unit.”
Kate confessed she had to tread carefully when being introduced to the children’s lives after they lost their mother Rebecca to breast cancer in May 2015.
She was just 34 when she died.
In the early days of her relationship with Rio, she admits one of his children told her: “You don’t know how to look after children because you don’t have any.”
She admitted it was difficult to hear: “That upset me. But touch wood, they wouldn’t say that now. They know how much I do for them; I bring fun into their lives.”
After initially keeping their romance out of the public eye, Kate decided to quit TOWIE in September 2017 to focus on being a girlfriend and stepmother.
Explaining her decision, she said: “It didn’t feel right for the children to see their dad’s girlfriend out and about, creating all this drama on TV.
“Playing out your relationship with your ex on TV is never a good thing.”