Meghan and Harry delighted to welcome a son

The Duke and Duchess of Sussex will be thrilled to have a boy.

The arrival of a son was a surprise for proud parents Meghan and Harry, who chose not to find out their baby's sex beforehand.

American former actress Meghan had already indicated they would be delighted with either a girl or a boy.

The duchess is a proud feminist, and committed to promoting women's empowerment, and will no doubt look forward to passing the message on to her son.

On International Women's Day, she talked about the male role in working together on gender equality, adding: "I think that men are part of the conversation – my husband certainly is."

The ex-Suits star described how she watched a "documentary about feminism on Netflix and one of the things they said during pregnancy was 'I feel the embryonic kicking of feminism'".

She said, as part of a panel of feminists and national figures: "I loved that – boy or girl, whatever it is, we hope that's the case."

As a first-born boy, the new addition to the Sussex family will one day succeed Harry as the Duke of Sussex.

First-born girls are not currently entitled to inherit hereditary peerages, although the Daughters' Rights pressure group is taking the Government to the European Court of Human Rights over the issue.

Baby Sussex is not a prince or an HRH because George V limited titles within the royal family more than 100 years ago.

His title is expected to be Earl of Dumbarton – as the son of a duke, he is entitled to use one of Harry's lesser titles.

The Scottish title – which refers to Dumbarton on the north bank of the River Clyde, to the west of Glasgow – was given to Harry by the Queen on the morning of his wedding.

The baby's surname is expected to be Mountbatten-Windsor.

Harry is already a godfather to a number of youngsters including Jasper Dyer, a pageboy at the royal wedding and the son of the duke's mentor, Mark Dyer.

The couple also asked Brian and John Mulroney to be pageboys – the twins are the sons of Meghan's best friend, Jessica Mulroney.

An uncle to Prince George, Prince Charlotte and Prince Louis, Harry has been praised for his relationship with George by former US first lady Michelle Obama.

Mrs Obama said of the duke after witnessing them together in 2016: "I have to say the most precious thing, if you haven't already fallen in love with him, is to see him with his nephew."

A baby boy means Charlotte remains the only girl among the Prince of Wales's four grandchildren.

Charles now has three grandsons – George, Louis and Baby Sussex.

Bookmakers were convinced that Harry and Meghan were expecting a daughter, but punters will now be betting that the couple will take inspiration from royal history when naming their son.

Arthur is one of the favourites at the bookmakers – as are Edward, James and Albert.

Other possibilities include a tribute to Harry's father, the Prince of Wales, with Charles, or the baby's great-grandfather, the Duke of Edinburgh, with Philip.

The duke could also pay his respects to his late mother Diana, Princess ­­of Wales, who died in a car crash when he was 12, by using Spencer – the princess's family name.

It is thought unlikely that Meghan will honour her estranged father, Thomas Markle.

But the LA-born former actress may decide to draw on American culture when picking a name.

The baby will only become a prince if the Queen steps in at the last minute by issuing a Letters Patent under the Great Seal of the Realm.

If this happens, the baby will become history's first Prince of Sussex.

The previous 19th century Duke of Sussex – an eccentric son of King George III – had both his marriages deemed illegal.

His mistress, Lady Augusta Murray, was not the Duchess of Sussex and his illegitimate son was plain Master Augustus Frederick d'Este.

Lady Augusta did, however, continually refer to herself as a duchess and a princess, and staff called her son Prince Augustus and her daughter Princess Augusta.

Baby Sussex will one day be entitled to become an HRH and a prince when his grandfather Charles eventually becomes King, but he or his parents could decide to keep his current title instead.

The Earl of Wessex's youngest son, Viscount Severn, is, as the child of a son of the sovereign, entitled to be known as Prince James.

But Edward and Sophie decided, with the Queen's agreement, that their children would use the courtesy titles of the children of an earl instead.

The new baby is seventh in line to the throne.