UK: Queen Elizabeth's 8 grandchildren hold vigil, Prince Harry in military attire (VIDEO)

Queen Elizabeth II's eight grandchildren held a vigil around her coffin on Saturday, two days before the late monarch's funeral.

US President Joe Biden also arrived in the United Kingdom on Saturday ahead of the memorial event and is expected to pay tribute at her coffin on Sunday.

Members of the public queued for up to 25 hours to pay their last respects in London's Westminster Hall.

Queen Elizabeth's grandchildren, aged from 44 to 14, stood by the coffin.  This include King Charles' two sons, Prince William and Prince Harry.

Prince Harry stood guard at the vigil wearing the uniform of the Blues and Royals cavalry regiment. The prince served in the British army in Afghanistan. Harry was stripped of his higher-ranking honorary military titles when he stepped down as a working member of the Royal Family.

The vigil came hours after King Charles and Prince William thanked those who had queued overnight.

"It means an awful lot that you're here," William tweeted.

Camilla hails queen as 'solitary woman' in male-dominated world

Queen Consort Camilla hailed Queen Elizabeth II as a "solitary woman" that "carved her own role."

"She's been part of our lives forever. I'm 75 now and I can't remember anyone except The Queen being there," Camilla said.

"It must have been so difficult for her being a solitary woman," she said.

"There weren't women prime ministers or presidents. She was the only one so I think she carved her own role."

Camilla said that she will always remember the late queen's smile. "That smile is unforgettable," she said.