Donning a primrose yellow Alexander McQueen coat, Kate was accompanied by members of the wedding party, which includes her two older children, Prince George, 4, and Princess Charlotte, 3.
Kate's hat was designed by Philip Treacy and her shoes by Jimmy Choo.
Kate, 36, gave birth to her third child, Prince Louis, on April 23. Her husband Prince William, 35, served as his brother's best man at the wedding Saturday. The weeks-old little prince was not present at the wedding festivities today.ReutersCatherine, The Duchess of Cambridge arrives at St George's Chapel at Windsor Castle for the wedding of Meghan Markle and Prince Harry in Windsor, May 19, 2018. Inside Prince Harry and Meghan Markle's royal wedding Prince Harry, Meghan Markle get new royal titles from Queen Elizabeth
Kate and Markle have reportedly had a blossoming friendship, with Kate guiding Markle as she transitions into royal life.
In their first interview after announcing their engagement, Harry and Markle addressed the friendship between the former actress and Kate.SLIDESHOW: Prince Harry and Meghan Markle's Royal Wedding
“William was longing to meet her and so was Catherine, so you know being our neighbors, we managed to get that in a couple of, well quite a few times now and Catherine has been absolutely," Harry said, with Meghan chiming in to say, "She’s been wonderful.”
Harry added he is grateful for the "fantastic support" of his brother and sister-in-law, describing it as "amazing."James Gourley/REX/ShutterstockPrince Harry and Prince William arrive for the royal wedding Windsor, May 19, 2018.
Markle, who was known for her humanitarian work prior to meeting Harry, will join him, Prince William and Princess Kate as a patron of The Royal Foundation.