Kate Middleton in Early Stages of Labor

Kate Middleton is ready to give birth.

The Duchess of Cambridge was admitted to St. Mary's Hospital at 6 a.m. local time today in the early stages of labor, according to Kensington Palace. She traveled by car from the palace to the hospital with Prince William, the Duke of Cambridge, palace officials said.

"So exciting, after months of waiting, we're finally here and we're finally in the last stages of the wait time," royal contributor Victoria Murphy told ABC News. "Very soon, we're going to find out if she had a boy or girl."

Boy or girl -- even Prince William, 32, and Kate, 33, don't know the gender -- this child will be fourth in line to the throne, bumping Prince Harry down to fifth. As was the case with Prince George in July 2013, the Duchess of Cambridge is expected to give birth in the Lindo Wing of St. Mary's Hospital in Paddington.

There will be a formal announcement including the baby's gender, weight and time of birth that will come after the queen, the royal family and the Middletons have been informed. His or her name is likely to come after.

Kate and William haven't decided yet whether they will bring Prince George to visit his baby sibling at the hospital but, if history is any indication, the Duke of Cambridge visited Princess Diana and a newborn Harry more than 30 years ago.

Time will tell what the royals will say after the birth of their second child. When Prince George was born, the new parents opened up about their bundle of joy to well-wishers outside of the hospital.

"He's got a good pair of lungs on him. He's a big boy, he's quite heavy," William said at the time. "He has her good looks, thankfully!"

Added Kate: "It's very emotional. It's such a special time, I think any parent will know what this feeling feels like."