Queen Elizabeth II arrives at Buckingham Palace ahead of royal baby's birth

Queen Elizabeth II arrives at Buckingham Palace on July 22, 2013, in London.
Jordan Mansfield/Getty Images

Queen Elizabeth II arrived by car at Buckingham Palace on Monday, as her grandson's wife is in labor with the next royal heir.

The monarch, 87, was photographed being driven to the palace in an SUV.

She'll become a great-grandmother for the third time when Prince William and Kate, Duchess of Cambridge, welcome their first child. Kate, 31, was admitted to St. Mary's Hospital in London earlier Monday, with William by her side.

"Her Royal Highness The Duchess of Cambridge has been admitted this morning to St. Mary's Hospital, Paddington, London in the early stages of labour," the announcement from Kensington Palace said. "The Duchess travelled by car from Kensington Palace to the Lindo Wing at St Mary's Hospital with The Duke of Cambridge."

The palace said her labor is progressing normally, according to the BBC.

Last week, the queen was asked by a young schoolgirl if she wanted Kate's baby to be a boy or a girl -- and said she didn't have a preference, though she hoped the baby would be born soon. 

"I don't think I mind," she responded. "I would very much like it to arrive. I'm going on holiday."

The baby will be third-in-line to Britain's throne, regardless of gender, behind William and his father, Prince Charles.