Queen Elizabeth II is suffering from "episodic mobility problems" and will not attend the opening of Parliament, Buckingham Palace announced on Monday.

    Instead, Prince Charles will appear in her place on Tuesday and deliver a speech with his son, Prince William, in attendance.

The 96-year-old monarch recently celebrated the 70-year mark of her time on the throne.

    "The Queen continues to experience episodic mobility problems, and in consultation with her doctors has reluctantly decided that she will not attend the State Opening of Parliament tomorrow," according to the Buckingham Palace statement.

    "At Her Majesty’s request, and with the agreement of the relevant authorities, The Prince of Wales will read The Queen’s speech on Her Majesty’s behalf, with The Duke of Cambridge also in attendance. " Queen Elizabeth II became the longest reigning monarch in British history in 2015, surpassing her great-great grandmother, Queen Victoria.

    It's been a little more than a year since the queen's husband, Prince Philip, died at age 99. He had been the longest-serving consort of any British monarch.