Kate Middleton stands out in white at Trooping the Colour

Princess Kate stepped out in style Saturday at Trooping the Colour .

For her first public appearance since announcing her cancer diagnosis in March, Kate turned to one of her go-to designers , Jenny Packham.

The princess wore a white Jenny Packham dress with a black trim and a black bow.

She accented the dress with a matching white hat by Philip Treacy.

Kate joined her children, Prince George , Princess Charlotte and Prince Louis , and her husband Prince William as well as other royal family members, including King Charles III and Queen Camilla, at this year's Trooping the Colour.

During the parade, Kate rode with George, Charlotte and Louis in a state carriage down the Mall.

In the first update on her health since announcing her cancer diagnosis, Kate said Friday that she is "making good progress" as she undergoes chemotherapy but is not "out of the woods yet."

"I am making good progress, but as anyone going through chemotherapy will know, there are good days and bad days," Kate said in a written message shared by Kensington Palace. "On those bad days you feel weak, tired and you have to give in to your body resting. But on the good days, when you feel stronger, you want to make the most of feeling well."

Kate said her treatment will continue "for a few more months," adding, "On the days I feel well enough, it is a joy to engage with school life, spend personal time on the things that give me energy and positivity, as well as starting to do a little work from home."

Kate's appearance at Trooping the Colour is the first time she has been seen publicly with the royal family since December, when she and her family attended a Christmas Day service in Sandringham.