KING Charles standing shoulder to shoulder with Princess Kate proves they're fighting together in unprecedented times, a royal expert says.
Beaming Kate stood next to Charles on the Buckingham Palace balcony this afternoon as they waved to cheering crowds.
Adoring fans erupted as the royals stepped out for the monarch's birthday in Kate's first public appearance since Christmas.
It was the first time Princess Kate had attended a public royal event since she and Charles were diagnosed with cancer.
Royal expert Richard Fitzwilliams said the late Queen would have been proud of Charles and Kate's "gesture of solidarity".
Richard told The Sun: "What I think the image I think so many people will have is of Catherine standing next to King Charles on the balcony.
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"This can be interpreted as a gesture of solidarity and support from Charles to Catherine.
"Let's be frank. It would have been very stressful to go through with all of the ceremony.
"It's all in the eye of a worldwide media storm. Britain is known for its ceremonial brilliance.
"King Charles and the Princess of Wales knew very well every movement would be photographed that was public.
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"Point was obviously that this was something that went very successfully, and the image was of absolute solidarity."
Richard added: "The monarchy has in recent years had cope with serious illnesses.
"They've had trouble - problems with the Sussexes and with Prince Andrew.
"But this was very different, and you could see the solidarity and the sympathy.
Lower than vermin Kate trolls must stop their vile vitriol after Princess’ brave appearance today - but I fear they’ll never be satisfied, expert says
ROYAL expert Richard Fitzwilliams slammed the shameless trolls who have hounded Kate during her illness.
Richard told The Sun: "I mean they are lower than vermin to coin a phrase.
"But one has to accept that trolls are part and parcel of social media life.
"Unfortunately, I wish there was a way that it could be better policed, but there isn't one.
"I mean, I think there will be less of it, because people obviously can see for themselves.
"But I despair at the moment of it ever vanishing."
"I would pay it the highest possible compliment - I believe the late Queen would have been proud of the way they handled it."
Charles and Kate stood tall at each other's sides this afternoon, waving to thousands of well-wishers.
The day had been plagued by rain but downpours couldn't dampen Kate's shine as she beamed alongside Prince William and their kids.
Kate was seen joking and laughing with Prince George, 10, Princess Charlotte, nine, and six-year-old Prince Louis.
And when they stepped out on the balcony alongside the rest of the Royal Family, crowds roared.
Duty & family mean everything to Kate
By ARTHUR EDWARDS, Sun Royal Photographer
THE Royals were one big happy family on the Buckingham Palace balcony as the Princess of Wales made an emotional one-off appearance.
This was a brave return to public life for Catherine, who has valiantly battled cancer for the last three months.
She did not have to be at Trooping the Colour and no one would have blamed her for staying away.
But she still chose to attend.
It is a measure of just how much her duty and family mean to her.
I have not seen the Princess of Wales in person since her last public engagement on Christmas Day, more than six months ago.
Yesterday she looked very well and, crucially, very healthy too.
While the photo released on Friday by Kensington Palace was a solemn snap, yesterday Catherine beamed with joy – her smile will undoubtedly warm the nation’s heart.
Accompanied by William, who has soldiered on alone while supporting his sick wife, and her adorable children, the whole group looked relaxed and united throughout one of the most important days of the year for the Royal Family.
It was also lovely to see Catherine exchanging words with her father-in-law King Charles.
Both of them battled hard to return to their duties and even through a long lens you can tell they have genuine warmth for each other.
The only downside was the classically British weather.
It was cold.
It was wet.
My jacket and my camera were soaked.
Next Thursday will be the longest day of the year but the driving rain made me feel like I was in the middle of January.
Yet the moment the Princess emerged to wave and smile, it made bearing the downpour worthwhile.
There were a lot of smart outfits on show – it was a military parade after all – but the Princess of Wales’ stunning white dress was a cut above everyone else’s.
Almost every camera there was fixed on her and with exceptional taste she picked out a dress that could be seen down The Mall by thousands of well-wishers.
This was a remarkable return by a remarkable woman and I'm sure it would’ve meant the world to have her family by her side.
So it’s no surprise that she didn’t stop smiling throughout.
The princess was seen beaming ear to ear alongside "devoted" Wills, with their children mirroring them.
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Sweet Princes George and Louis waved with two hands to crowds with their sister at their side.
They all watched on as more than 30 aircraft took to the skies as part of the celebrations - including a tribute to a fallen RAF pilot.