Duchess of Cambridge
Kate Middleton, Prince William and Prince Harry were just some of the 2,200 attendees at the Westminster Abbey ceremony.
The 8-year-old joined her parents, the Prince and Princess of Wales, and her siblings for the big day.
The King and Queen weren't the only ones in a special 'fit.
She comes to serve, not be served.
The supporter was reportedly unable to fly from America to the UK for this weekend's historic ceremony due to a broken leg.
The Prince and Princess of Wales marked the special occasion by sharing a picture taken by Kate over the weekend.
The Prince and Princess of Wales celebrated 12 years of marriage on Saturday.
Newcomers Ed McVey and Meg Bellamy will portray the royal couple in their St Andrew's days.
The next in line to the British royal throne even took to the kitchen to help make handmade roti.
Sunday marked the first time the four-year-old prince accompanied his family to Easter church services.
About Duchess of Cambridge
Born on January 9 1982, the Duchess of Cambridge is five months older than Prince William. The pair married on 29 April 2011, having met at Scotland's University of St Andrews in 2001. The couple split briefly in 2007, but later reunited and became engaged during a holiday in Kenya to celebrate the Prince passing his RAF helicopter search and rescue course. On 14 January 2013, St James's Palace announced that the Duchess was expecting her first child in July 2013.