Meghan Markle, Prince Harry expecting first baby

Prince Harry and Meghan Markle, the Duke and Duchess of Sussex, are expecting their first child in the spring of 2019, according to a Twitter message posted Monday by Kensington Palace.

“Their Royal Highnesses The Duke and Duchess of Sussex are very pleased to announce that The Duchess of Sussex is expecting a baby in the Spring of 2019,” the palace tweeted.

The baby will be the first child for the couple, who were married May 19 in a grand ceremony in St. George’s Chapel at Windsor Castle in Britain.

"Their royal highnesses have appreciated all of the support they have received from people around the world since their wedding in May and are delighted to be able to share this happy news with the public," Kensington Palace said in a statement. It added that Doria Ragland, Markle's mother, "is very happy about this lovely news and she looks forward to welcoming her first grandchild."

"My warmest congratulations to the Duke and Duchess of Sussex on the happy news they are expecting a baby in the Spring. Wishing them all the best," British Prime Minister Theresa May tweeted upon hearing the news.

The baby will be seventh-in-line to the British throne, Reuters UK reported.

The prince, 34, is a son of Prince Charles and of the late Princess Diana, who died in 1997. Harry is a grandson of Queen Elizabeth II and Prince Philip.

His brother, Prince William, and sister-in-law, Kate Middleton, have three children: George, Charlotte and Louis.

Markle, 37, is an American actress who was born in Los Angeles.

Just days after watching Harry's cousin Princess Eugenie tie the knot with Jack Brooksbank at St. George's Chapel, Windsor Castle near London, the newly expectant couple arrived in Sydney for the first stop of a 16-day tour of Australia and the South Pacific. Hundreds of people gathered to catch a glimpse of the couple after they landed.

Their tour will coincide with the Invictus Games, a Paralympic-style sport event for wounded veterans from around the world. Prince Harry, who served two tours in Afghanistan, founded the games in 2014. The Kingdom Choir, which performed at Markle's nuptials to Prince Harry back in May, will perform at the games' closing ceremony on Oct. 27.

The Associated Press contributed to this report.