LONDON — Newlyweds Prince Harry and Meghan Markle are expecting a baby in the spring, the royal household announced on Monday.

The news came as the couple arrived in Sydney at the start of a 16-day tour of the South Pacific and Australia, a constitutional monarchy whose head of state is Harry's grandmother, Queen Elizabeth II.

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. pic.twitter.com/Ut9C0RagLk — Kensington Palace (@KensingtonRoyal) October 15, 2018

The new baby will be seventh in line to the throne, after Harry and first cousins, Princes George and Louis and Princess Charlotte.

"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," according to a statement from Kensington Palace.

Prince Harry has made no secret of wanting to start a family. In an interview with the BBC in November 2017, after announcing their engagement, Harry was asked if he and Meghan had talked about having children.

"Of course, one step at a time and hopefully we'll start a family in the near future," he responded.

On Monday, the two walked out of the airport hand in hand as crowds lined the streets to catch a glimpse of their car. They will visit cities around Australia, and Harry is scheduled to speak at the opening of the Invictus Games, which he created for wounded service personnel. They will then travel to Fiji, Tonga and New Zealand.

Kensington Palace said Meghan's mother, Doria Ragland, is "very happy" at the news. She was in London last month to visit her daughter and joined Meghan and Harry at the launch of a cookbook supporting the survivors of the Grenfell tower block fire.

The royal couple were also congratulated by British prime minister, Theresa May, as well as the American ambassador to the U.K.

The duke and duchess wed on May 19 at Windsor Castle. Their star-studded celebrations drew attention from around the world as around 100,000 people crowded the streets of Windsor, including many Americans who flew in specially for the big day.

This past weekend, they attended the wedding of Harry's first cousin, Princess Eugenie, which like theirs, took place in St. George's Chapel in Windsor.

Harry and Meghan — along with Prince William and his wife, Kate, the Duchess of Cambridge — are taking on more royal duties; the queen, who is 92, has reduced her travel and public duties and her husband Prince Philip retired in August.

Prince Charles and his wife Camilla attract less attention than the younger royals, though they are two of the most active members of the royal family.

Since the duke and duchess announced their engagement, they have been busy supporting various causes and charities. Last month, the duchess attended her first solo engagement, the opening of an exhibition of South Pacific art at the Royal Academy of Art.

In August, Harry made an appearance on stage at a performance of Hamilton.

The duchess, who is mixed race and was previously married, has been hailed as a modern addition to an old institution. She's been warmly welcomed by the British public and the royal family. One of her first engagements after the wedding was a trip to the northwest of England with the queen.