The Duke and Duchess Of Cambridge have welcomed a baby boy, the Kensington Royal Twitter account has confirmed.
"Her Royal Highness The Duchess of Cambridge was safely delivered of a son at 1101hrs," the official account confirmed. "The baby weighs 8lbs 7oz."
"The Duke of Cambridge was present for the birth," they went on to say. "Her Royal Highness and her child are both doing well."
The account also confirmed that the royal family is delighted by the news.
"The Queen, The Duke of Edinburgh, The Prince of Wales, The Duchess of Cornwall, Prince Harry and members of both families have been informed and are delighted with the news," they added.
Earlier in the day, the official Twitter account confirmed that Kate had gone into labour, and showed a picture of the world's media lining up outside of St. Mary’s Hospital in London for a first glimpse of the little one, which is expected to come later today or early tomorrow.
A name for the tot has yet to be revealed, but is likely to be announced in the coming hours. The Duke and Duchess are also expected to pose with their new arrival on the steps outside the Lindo Wing, as is royal tradition.
The infant is a sibling for the couple's four-year-old son Prince George and their two-year-old daughter Princess Charlotte. Accordingly, the baby is fifth in line to the throne and Queen Elizabeth II's sixth great-grandchild.
The royal couple announced they were expecting their third child in September as Kate, 36, had to pull out of an engagement as she was suffering from hyperemesis gravidarum, or severe morning sickness, as she did with her previous two children.
She has been on maternity leave since 22 March and was noticeably absent from The Queen's birthday concert at London's Royal Albert Hall over the weekend.
William, 35, and Kate married in 2011.