Tuvalu (CNN) -- "Keep calm and carry on" is a catchphrase that Britain first adopted during World War II -- and while the country may not be at war anymore, it's become a motto as we continue to fight our own personal battles.
The Duchess of Cambridge redefined the spirit of the phrase in the past week -- her new motto could easily be: "Keep calm and carry on with a smile."
You can only imagine what was going through her mind when she stepped out in front of a vast media presence in Kuala Lumpur last Friday, knowing everyone there had seen pictures of her topless, after photos of her on holiday were published overnight in a French magazine.
A palace source said she was upset. The irony, of course, was that that day she was dressed as conservatively as she could be, because she was visiting a mosque.
I've watched Kate up close for the past year and a half and seen how she conducts herself in public in the context of the frenzy around her; in fact, I am part of it. There is no way I could look that calm and collected knowing that everything I was doing was being scrutinized in such detail.
She performs impeccably every time. She never stumbles and always makes it look easy. She copes by being in control. She prepares assiduously for everything she does in public and knows exactly what's expected of her and where her limits are.
Make no mistake, the Duchess of Cambridge is smart as a button and a natural public figure. But what I didn't realize was just how steely her character was. She has not just become a member of the royal family -- she's becoming its anchor.
William was less able to hide his emotions. At the airport as he left Kuala Lumpur, he had a face like thunder. He was furious with Closer magazine for violating the couple's privacy and humiliating his wife. He had spent the day locked in discussions behind the scenes with a view to suing the magazine, commandeering the original photos and prosecuting the editor and photographer.
This was something neither of them was going to take lying down. A red line had been crossed, the palace told me.
By the time the couple reached Borneo they had relaxed a bit. Perhaps it was the isolation of the jungle, but William even had time to joke with an approved photographer who was dangling from a tree.
William may work with the media, but he hates the paparazzi. This goes back to his childhood, where even at primary school he was overheard moaning about "'tographers." It was also the French paparazzi who pursued his mother and surrounded her car as she lay dying following a crash in Paris.
Kate's strength is that she doesn't have William's background. She was brought up out of the public eye in the idyllic Berkshire countryside with a stable, happy family. She was only exposed to media intrusion as a grown up, when she was better armed to handle it.
That doesn't mean it's been easy for her. Before she was married, she fled London because she was being pursued so aggressively by paps, with all the vile expletives they use grab attention. But she does have a strength of character that allows her to cope, and that's a virtue that was on full display here in the Solomon Islands. She is bolstering her understandably more fragile husband.
When they arrived here the Duke and Duchess received a rapturous welcome. I met them and they were clearly heartened by their reception and managing to put the legal battle at the back of their minds, at least in public.
By the time they reached the final stop on their Asian tour, and news came in that they had won their civil case against Closer, they completely let go, dancing and giggling away.
When the phrase "Keep calm and carry on" was first adopted it was all about hiding your emotions with a straight face. Kate and William are doing that with a smile. In Tuvalu, they weren't just coping -- they were separating their public and their private lives, and that's what they want the media to do.
William will one day be king and is taking on more and more responsibilities from his grandmother. In Kate, he has found his "strength and stay" -- a phrase the Queen used to describe her own husband and rock Prince Philip.
This tour has shown William couldn't have found anyone stronger in his future queen.