Prince Edward's wife the Countess of Wessex has given birth to a baby boy, Buckingham Palace has announced.
A spokesman said the couple are "absolutely thrilled"
Sophie, 42, gave birth by caesarean section at 1620 on Monday at the Frimley Park NHS hospital in Surrey.
The child, who weighed 6lbs 2oz (2.8kg), is eighth in the line to the throne. Prince Edward said he was "very cute and very cuddly".
The couple, who also have a four-year-old daughter Lady Louise Windsor, have not yet named the baby.
Sophie and her son are expected to stay in hospital for the next few days. The child is likely to take the title Viscount Severn.
Prince Edward was present at the birth and, speaking afterwards, said it had been "a lot calmer than last time" and that his wife was "doing very well".
He also said he was relieved, and added that his son was "like most babies, rather small, very cute and very cuddly".
'Delighted' royal in-laws
When asked about a potential name he said: "We didn't know, we had no idea what we were going to get, we hadn't asked.
"You have to at least get to know the small person who's just come into the world before you actually try and pick a name."
Sophie and Edward's daughter was born four weeks premature in 2003.
The countess had suffered a life-threatening ectopic pregnancy in 2001 before becoming pregnant with Lady Louise.
The Queen and Duke of Edinburgh and Sophie's father, Christopher Rhys Jones, have been informed and are also said to be "delighted" with the news.
Sophie Rhys-Jones married Prince Edward at St George's Chapel in Windsor in June 1999. They met at a tennis event in the summer of 1993.