She died on Thursday in her Balmoral estate in Scotland at age 96. She served as queen since 1952. Her passing ended the longest-reining monarchy in British history.
The funeral service will take place at Westminster Abbey, a royal church in the center of London. President Biden and other world leaders are expected to attend. The U.K. has declared Sept. 19 a holiday in honor of the queen.
Prior to the service, Elizabeth will lie in state inside Westminster Hall for four days to allow the public to pay their respects.
In a statement on Twitter, Elizabeth's grandson, Prince William, wrote that it will take some time before the reality of life without his grandmother will sink in.
"While I will grieve her loss, I also feel incredibly grateful. I have had the benefit of The Queen's wisdom and reassurance into my fifth decade," he wrote.
William added that he looks forward to supporting his father's new title as King Charles III, which was officially announced earlier Saturday.