The royal couple's trip Down Under is their only global tour since they were married, apart from a two-day visit to Ireland. She said that "I think it's lovely that they're having a family so soon".
TV stations broke away from their Brexit coverage, banner headlines appeared on newspaper websites, and bookmakers began taking bets on the name of the future seventh in line to the British throne.
The Duke and Duchess are touring Australia for the next nine days, primarily for the Invictus Games in Sydney.More news: Khabib Nurmagomedov challenges Floyd Mayweather to clash
Kensington Palace said that "The Queen, Duke of Edinburgh, Prince of Wales, Duchess of Cornwall and Duke and Duchess of Cambridge are delighted for the couple and were able to congratulate them at the wedding in person".
Mr Woo told the Duchess about his three children, saying "there's no rest but it's so rewarding", to which Meghan smiled.
She said in a 2016 interview that becoming a mother was on her "bucket list". "I wish them both good luck".
He said: "She's wanted children for a long time".More news: Enjoy afternoon tea at funeral directors and help breast cancer charity
The internet broke again as soon as the photos of the much-awaited debut of Meghan Markle's baby bump.
Susan Pyper, Lord-Lieutenant of West Sussex said: "I was delighted to hear today's announcement that Their Royal Highnesses The Duke and Duchess of Sussex are expecting a baby next spring".
They will also visit New Zealand as well as Tonga and Fiji - two areas where there is a risk of Zika virus transmission.
The sporting event founded by Harry in 2014 gives sick and injured military personnel and veterans the opportunity to compete in sports. "Looking forward to sharing in the joy during your stay down under", he tweeted on Monday evening.More news: Usain Bolt offered two year contract with Champions League-chasing side agent