Prince William Remembers 'Grannie,' Queen Elizabeth, Pledges to Support King Charles

Prince William is speaking out about the death of Queen Elizabeth II, and pledging his support for the new king — his father, King Charles III.

On social media, William wrote, "On Thursday, the world lost an extraordinary leader, whose commitment to the country, the Realms and the Commonwealth was absolute. So much will be said in he day ahead about the meaning of her historic reign."

"I, however, have lost a grandmother," he went on. "And while I will grieve her loss, I also feel incredibly grateful. I have had he benefit of The Queen's wisdom and reassurance into my fifth decade."

Mentioning his wife, Kate Middleton, he said, "My wife has had twenty years of her guidance and support."

He went on, "My three children have got to spend holidays with her and create memories that will last their whole lives. She was by my side at my happiest moments. And she was by my side during the saddest days of my life."

Touchingly, he said, "I knew this day would come, but it will be some time before the reality of life without Grannie will truly feel real."

Addressing the historic nature of the end of Elizabeth's reign, William sought to reassure Britons: "I will honour her memory by supporting my father, The King, in every way I can."

Read his entire statement:

The personal statement was William's first since Elizabeth II died peacefully on Thursday at Balmoral Castle.

On Saturday morning, his father, King Charles III, was formally made monarch during a two-part ceremony.

Along with Charles' ascension to the role of King, William and Kate are now the Duke and Duchess of Cornwall and Cambridge.

The Duke of Cornwall is a position typically held by the heir to the throne, and Charles had held the title since 1952.

William and Kate are combining their new role with their previous titles as the Duke and Duchess of Cambridge, positions they have held since their April 2011 wedding.

The couple's social media accounts are already reflecting the change.

People reports that William and Kate will likely inherit the titles Prince and Princess of Wales, previously held by Charles and his late ex-wife Princess Diana.

The title, typically held by the male heir to the throne, doesn't automatically get passed on; it must be given by the sovereign.