The Princess of Wales's trip to Italy has been a reminder of how much the royals need her star quality.
The visit to Reggio Emilia had been hailed as significant as her first overseas trip since her cancer diagnosis and treatment. It was her comeback tour, framed by her team as a "huge moment".
But what the trip to Italy soon revealed was how important her glamour and popular appeal is to the Royal Family.
She is a splash of movie-star colour and it's her face that the newspapers want to put on their front pages.
Italians who waited to see her arrival on Thursday credited her sincerity and empathy as among the reasons they had tried to catch a glimpse of her.
It's hard to pin down that mystery ingredient. But it was enough to draw crowds to see her in this northern Italian city, on what otherwise would have been a low-key fact-finding trip about an early years education project.
On Thursday morning, on a dusty side street on the outskirts of Reggio Emilia, in an everyday kind of place, there were crowds lined up behind barriers, awaiting her arrival.
"Principessa, principessa," chanted some of the children in the crowd, as a big black BMW drew up in a convoy of police vehicles.
Catherine stepped out, smiling and waving, working her way along a line of greeters, before stepping into an industrial-looking building.
She was visiting a project that recycled materials and products to be used in education, as part of her information gathering about Reggio Emilia's approach to teaching young children.
Outside, under the eye of the carabinieri and a phalanx of photographers, the crowd waited. Some had dressed up in fancy hats and outfits, some held up posters. More barriers were brought out as the crowd grew.
About an hour later, the princess emerged to even louder applause, waving again, before disappearing off to the next stage of her trip. Well-wishers held out their flowers like jilted lovers.
When she had gone on a walkabout in the town square on Wednesday, it had been even more intense, with a crowd of more than a thousand all seeming to want to shake hands and have a selfie with Catherine.
Why did Italians show so much interest in Catherine?
In the crowd on Thursday, Maria Theresa said she had travelled from Rome to see Catherine.
It was the princess's sense of empathy with other people that had made her want to see her in person.
"Italians like her. We're people of emotions," she said, adding that she felt the princess was "close to the people".
Maria Theresa thought Catherine's interest in helping young people showed she was a "humanitarian" and that her own views about life connected with Catherine's.
Catherine did not make any speeches or do any interviews during the trip, but this supporter spoke as if they knew each other.
"She's a wonderful woman and so beautiful," said Georgia, who had come from Modena. "She reminds us of Diana."
Also from Modena was Chiara, who said "it was nice to see her looking well now" and described the princess as "strong and kind". The two women had dressed up and worn badges about the royals for the occasion.
In Italy, where she has no public role, Catherine seemed to fascinate people. Whether it was her social causes or her fashion choices, there seemed to be interest.
Here she was seen by well-wishers as being supportive of those in need and on the side of the vulnerable. The story of her illness seemed to have connected. People believed it gave her a sense of understanding.
A woman who wished not to be named told me that she liked Catherine because the princess had not shown "fake empathy", of the kind associated with celebrities, but "real empathy".
A banner in the city's square had promised Catherine "love and support", as though she was a cause to be supported. Maybe it was a response to all Catherine's messages of support for those in need of help.
Catherine, who seemed to be enjoying the visit, issued a statement about how much it had meant to her.
"I have had such a deeply moving and unforgettable time here," she said. "Thank you to the people of Reggio Emilia for welcoming me into a culture of care with such warmth and generosity."
She had pushed all the buttons, making pasta, playing with children, listening and learning for her early childhood project, trying out her gap-year Italian language skills.
There must be many reasons that Italians came out in numbers to see her - not least because she's incredibly famous.
But this will be seen as a successful first trip back on the road, with more almost certainly in the pipeline to follow.
