Duchess Kate and Prince William introduce new prince on steps of Lindo Wing: See pics!

There's a new royal baby in town!

Duchess Kate and Prince William introduced their new son to the world on the steps of Lindo Wing of St. Mary's Hospital on Monday evening.

The Duchess of Cambridge wore a stunning red Jenny Packham dress with a lace collar that she matched with a pair of stilettos. The couple waved to the crowd as Kate held their new bundle of joy. After a couple of minutes, the trio went back inside the hospital.

See photos of the new prince!

Moments later, they emerged again, this time with baby No. 3 in a car seat, and they made their exit en route to Kensington Palace.

The introduction comes after Kate gave birth to their new bundle of joy late Monday morning. Britain's newest prince weighed 8lbs and 7oz, making him the heaviest royal baby to be born in over 100 years.

"Her Royal Highness The Duchess of Cambridge was safely delivered of a son at 1101hrs," the announcement read. "The baby weighs 8lbs 7oz. The Duke of Cambridge was present for the birth. Her Royal Highness and her child are both doing well."

Earlier this afternoon, William left St. Mary's Hospital to pick up Prince George and Princess Charlotte.

"Back in a minute," a smiling William told reporters.

He came back shortly after with George and Charlotte in tow, who looked totally adorable in their coordinating navy ensembles. On her way to the entrance of the Lindo Wing, Charlotte stole the show with her adorable waving. See photos of the moment here: