Britain's Duchess of Sussex, Meghan Markle, has given birth to a baby boy, with husband Prince Harry saying the couple are "absolutely thrilled".

Speaking at Windsor Castle, Prince Harry said they are still thinking about names following the baby's birth on Monday morning.

"The baby was a little bit overdue so we've had a little bit of time to think about it," said Prince Harry of deciding on a name. "That's the next bit."

He said he planned to make another announcement in two days' time "so everyone can see the baby". The couple chose not to find out whether they were having a boy or girl ahead of their son's birth.

Paying tribute to his wife, Prince Harry said: "It's been the most amazing experience I could ever have possibly imagined.

"It's been the most amazing experience I could ever have possibly imagined"

"How any woman does what they do is beyond comprehension. But we're both absolutely thrilled.

"We're both absolutely thrilled and so grateful for all the love and support from everybody out there, it's been amazing, so we just wanted to share this with everybody."

Buckingham Palace said the baby was born at 5:26am on Monday morning, weighing 7lbs, 3oz. The Duchess's mother, Doria Ragland, is with the couple at their Windsor residence, Frogmore Cottage.

The baby is the seventh in line to the throne, and Britain's Queen Elizabeth II and the Duke of Edinburgh's eighth great-grandchild, and a fourth grandchild for the Prince of Wales. 

The palace said the royal family and the family of Prince Harry's late mother, Diana, Princess of Wales, had been informed of the baby's birth and are "delighted with the news".

Meanwhile, The Duchess's father Thomas Markle, who is said to be estranged from his daughter and lives in Mexico, has told Britain's The Sun newspaper: ''I'm delighted to hear that mother and child are doing well.

"I am proud that my new grandson is born into the British royal family and I am sure that he will grow up to serve the crown and the people of Britain with grace, dignity, and honour.

"God bless the child and I wish him health and happiness, and my congratulations to my lovely daughter Duchess Meghan and Prince Harry, and God save the Queen.''

This will be his seventh grandchild.