The king and queen will remain in nearby Clarence House.
Buckingham Palace also released a new photograph of the King in honor of his big day.
All eyes were on Princess Kate Saturday as she made her first public appearance since her cancer diagnosis early this year.
A recently unveiled portrait of King Charles was vandalized in a London museum on Tuesday by an activist animal rights group, the group said.
The King's audio message were his first public comments since Catherine revealed she was undergoing chemotherapy. The princess' announcement put an end to months of speculation over her health.
How the royal family is moving forward after both King Charles and Princess Kate are diagnosed with cancer.