Claire dressed both Pippa Matthews - the Princess of Wales' sister - and Akshata Murty, the wife of Prime Minister Rishi Sunak amongst others attending Westminster Abbey to witness Charles III be crowned king.
Pippa's primrose yellow coat dress and matching fascinator was a hit with Royal fans many taking a social meeting to say how stunning she looked.
Her choice was a bespoke version, of the designer's Anais coat dress.
It was a bespoke short sleeve version of the Alexandra Dress that Akshata chose, in a soft blue jacquard.
Claire said: "We’ve have an outstanding reaction to both.
"It was an absolute pleasure to dress our clients, for such a momentous, British occasion."
She said that, as an independent British brand, it meant so much, to see Claire Mischevani pieces worn to such occasions.
"As all of the pieces are made in our own UK studios," she said.
"We are easily able to make adaptations to the lengths, necklines and sleeves, of our ready to wear collections. They are also available in a wide range of fabrics and colours."
Pippa’s attendance at the coronation was a rare public appearance. Married to James Matthews the couple have three children; four-year-old Arthur, Grace, two, and nine-month-old Rose.
The Shrewsbury dress designer has a five-floor boutique on Wyle Cop in Shrewsbury and a showroom in Chelsea.
Earlier this year Claire and her assistant were subjected to a terrifying ordeal when they were threatened by masked robbers in London.
They had been loading 62 designer pieces, including dresses and coats, into a car in Chester Row, SW1 at 8pm on Thursday following a fashion shoot. As they went in to get more items the gang broke into the car and ransacked it, taking property worth around £70,000.