Princess Catherine debuts new hairstyle and joins Prince William, King Charles for Garter Day

Princess Catherine debuted a new hairdo paired with an outfit last worn weeks ago as she joined an all-star cast of royals.

A radiant Princess Catherine waved on her handsome husband Prince William as the royals turned out in force for the tradition steeped Garter Day procession.

While Catherine opted to recycle an outfit she wore just last month for the VE Day concert – a stylish white Self Portrait dress – she nonetheless turned heads with her new hairdo.

The Princess, who has recently opted for sleek updo hairstyles – showed off gently waving mermaid-style locks which appeared to be longer than we’ve ever seen them before, spilling all the way down her back.

Britain's Catherine, Princess of Wales smiles as she attends the Order of the Garter service at St George's Chapel in Windsor Castle. Picture: AFP

Catherine and Prince Edward’s wife Sophie, the Duchess of Edinburgh, cheered on a host of royals from the sidelines who paraded to Windsor Castle for the Order of the Garter service.

As well Prince William, King Charles, Queen Camilla, Prince Edward and Princess Anne prominent individuals including former British Prime Minister Sir Tony Blair and famed composer Sir Andrew Lloyd Webber – both of who were appointed as Knight Companion of the Most Noble Order of the Garter – took part in the procession.

Princess Alexandra, The Honourable Lady Ogilvy, Sophie, Duchess of Edinburgh and Catherine, Princess of Wales shared a chat on the sidelines. Picture: Getty Images

Prince William, Anne, Princess Royal and Prince Richard, Duke of Gloucester walked together. Picture: Getty Images

Britain's King Charles III and Queen Camilla looked regal as usual. Picture: AP

“The King and the Knights process in grand velvet robes, glistening insignia and plumed hats within the grounds of Windsor Castle,” the Palace noted in a statement on Instagram.

“The Order of Garter was created nearly 700 years ago, in medieval times, by King Edward III.

“King Edward was so inspired by tales of King Arthur and the chivalry of the Knights of the Round Table that he set up his own group of honourable knights.”

Andrew Lloyd Webber was there in full regalia. Picture: Getty Images

So was Sir Tony Blair. Picture: Getty Images

Minor royals including first cousins of the late Queen Elizabeth, Princess Alexandra and Prince Richard were also in attendance for the splendid event which included a service in the same church where Prince Harry and Meghan Markle were married.

William and Kate made their exit in a carriage. Picture: AFP

KATE’S FIRM COMMAND TO PRINCE LOUIS

Princess Catherine had a firm order for Prince Louis during Saturday’s Trooping the Colour ceremony, according to a lip reader.

As the royal family gathered on the balcony of Buckingham Palace to watch the Royal Air Force’s flypast, the princess had to instruct Louis to stand at attention for the national anthem, according to lip reader Jeremy Freeman.

Prince George of Wales, Princess Charlotte of Wales and Catherine, Princess of Wales on the balcony of Buckingham Palace during Trooping The Colour. Picture: Getty Images

Trooping The Colour is a ceremonial parade celebrating the official birthday of the British Monarch. Picture: Getty Images

The mum of three said “National anthem. Louis, stand,” lip reader Jeremy Freeman told the Mirror.

Freeman told the publication as the historic event neared the end, the children appeared restless, prompting Catherine to ask: “National anthem. Louis, stand.”

Louis, 7, quickly straightened his posture and turned his attention to the anthem.

The event features over 1400 soldiers and officers, accompanied by 200 horses. More than 400 musicians from ten different bands and Corps of Drums march and while performing. Picture: Getty Images

According to Freeman, after the RAF flypast Prince William turned to his father King Charles and said, “Oh my word, what a day.” His father responded, “Great theatre.”

The King engaged with the Wales family, pointing to aircraft and asking, “What is that?”.

“Er, is that Poseidon?” William answered.

Prince George — who is learning to fly — joined in the conversation saying, “It’s a Poseidon, yeah.”

CHEEKY LOUIS’ QUIP TO GEORGE

Mischievous Prince Louis turned to his big brother Prince George for some quick advice during celebrations for his grandfather King Charles.

A lip reader has revealed the conversation cheeky Louis, seven, and George, 11, had as they arrived for the Trooping the Colour event in London on Saturday.

The Brothers were chatty and smiling as they made their way down the Mall in the Ascot Landau carriage in matching blue suits.

Prince Louis, left and Prince George leave Buckingham Palace. Picture: PA via AP

The young royals travelled in the carriage with mother Princess Catherine and sister Princess Charlotte, 10, to the cheers of the crowd.

According to a professional lip reader that spoke to The Sun, Louis asked George, “Should I wave?”.

George is said to have replied: “It’s up to you, I can’t believe how sunny it is”.

Louis then said “Let’s do it together” before the siblings waved to the crowds, the lip reader said.

Prince George of Wales and Prince Louis of Wales wore matching suits. Picture: Getty Images

Prince Louis smiles for the crowd. Picture: Getty Images

Catherine and Charlotte captivated royal fans as they twinned in blue and white outfits.

The Princess of Wales wore a dress coat featuring ivory contrast lapels and cuffs by London-based designer Catherine Walker. She paired the outfit with a wide-brimmed hat by London-based milliner Juliette Botterill.

Princess Catherine and Princess Charlotte twinned in blue. Picture: AFP

She accessorised with Queen Elizabeth’s Bahrain Pearl Drop Earrings and the Irish Guards Regimental Brooch.

Prince William took part in the official parade and looked unrecognisable in his bearskin hat.

William wore the Full Ceremonial Guard Order of the Welsh Guards as he arrived on horseback.

King Charles- who has a long-running tradition of saddling up for the annual celebrations – hung up his riding boots and arrived in a carriage instead.