US President Donald Trump has hailed the Princess of Wales as “so radiant and so healthy and so beautiful” as she glittered in gold at a state banquet in his honour.

Kate wore a couture creation by British designer Phillipa Lepley, with a striking full-length, champagne gold hand-embroidered Chantilly lace evening coat featuring a regal-looking high collar over a silk crepe gown for Wednesday night’s lavish dinner at Windsor Castle.

Trump made a point of referencing the princess, who announced back in January that she is in remission from cancer, in his banquet speech.

Trump sat in between Kate at the King at the banquet. She was seen smiling up at him as he delivered his speech.

“His Majesty has also raised a remarkable son in His Royal Highness, the Prince of Wales. Really amazing,” Trump said.

“We’ve gotten to know you and I think you’re going to have an unbelievable success in future.

“Melania and I are delighted to visit again with Prince William and to see Her Royal Highness, Princess Catherine, so radiant and so healthy, and so beautiful. It’s really a great honour, thank you.”

Kate beamed as she stood and raised her glass to toast Trump after his speech to the 160 guests in Windsor Castle’s St George’s Hall.

Her delicate coat featured hand-embroidered roses with couched gold cording, accented with French knots and satin-stitched blooms, demonstrating her commitment to supporting British craftsmanship and creativity.

Kate’s earrings belonged to the late Queen Elizabeth, while she opted for her go-to tiara, the Cambridge Lover’s Knot, and wore her hair down and styled in waves.

Earlier in the day, Trump appeared to tell future queen, Kate, “you’re so beautiful, so beautiful” as she and William greeted him and US first lady Melania Trump at the official start of the state visit.

The princess played a key role during the royal charm offensive deployed towards the US leader. She and William were the first to meet the Trumps from the official presidential helicopter, Marine One, on Wednesday morning. They walked with the American couple to see the King and Queen.

Heir to the throne William and Kate also held a “warm and friendly” private meeting with the Trumps in Windsor Castle after lunch. That engagement had not been previously announced as part of the official schedule.

The prince and first lady will step out later on Thursday for their first official appearance together.

They will meet British Scouts Association chief scout Dwayne Fields and young scoutsat Frogmore Gardens, a 13-hectare estate within the Home Park at Windsor Castle.

Kate has been joint president of the Scout Association since 2020.

She and Melania have both made children’s health and wellbeing a key focus of their respective roles.

For Wednesday’s banquet, Melania Trump opted for a fitted, more daring off-the-shoulder, long-sleeved vivid yellow gown, with contrasting wide pink buckled belt.

The Queen wore a royal blue silk marocain embroidered dress by Fiona Clare, and a sapphire and diamond tiara.

William was in a white tie and a Windsor tail coat, and a ceremonial sash and badge, along with miniature medals.

-with AAP