The Duke and Duchess of Cambridge debut third baby

The Duke and Duchess of Cambridge, Prince William and Kate Middleton stepped out of St. Mary's Hospital's private Lindo Wing along with the latest addition to the family.

The couple's third child, a baby boy, was born earlier today, weighing 8lbs 7oz, and the news of Kate's labour as well as the birth of the royal baby boy was announced by Kensington Palace.

Kate 36, was in labour for five hours, admitted to Lindo Wing around 6 am, delivering the baby at 11 am, making it a swift delivery, and the Duchess stayed in the hospital for just about 8 hours.

Previously with the birth of her first child Prince George, the Duchess stayed in the Lindo Wing for 22 hours, while with Princess Charlotte, Kate stayed for 11 hours.

Clad in a custom made Jenny Packham red dress with a floral lace neckline, the Duchess was beaming proudly as she cradled the new born in her arms, and Prince William was by her side, the couple looking obviously thrilled.

Kate had famously worn a blue polka-dotted dress when she debuted Prince George at the steps of St. Mary's, taking inspiration from Lady Diana who wore a similar ensemble at the birth of Prince William, while at the birth of Princess Charlotte, Kate opted for a sunshine yellow Jenny Packham dress.

Gorgeous and flawless, Kate did not look as if she had just given birth, and waved to onlookers who waited hours to catch a glimpse of the third royal baby.

With her diamond and sapphire engagement ring on, Kate was a beautiful sight in the red knee-length dress, styled with her signature nude heels, and her hair done in soft curls.

Kate's dress was certainly inspired by Princess Diana, who wore red with a white collar as she stepped out of the hospital following the birth of Prince Harry.

The couple debuted the baby on the steps of Lindo Wing, before going back inside and emerging few minutes later with the baby in a carry-cot.

Their new baby boy, whose name is yet to be revealed, was clad in a white bonnet and knit blanket, and seems to be as adorable as his siblings.

The new royal baby boy is fifth in line to the throne after his grandfather Prince of Wales, his father Prince William, and his siblings Prince George and Prince Charlotte, pushing his uncle Prince Henry down to sixth in line to the throne.