Royal watchers have flocked to the Sydney Opera House on Tuesday, following the announcement that Britain's Prince Harry and his wife Meghan are expecting a baby.

Kensington Palace has announced the pregnancy that the couple touched down in Sydney to kick off a 16-day tour revolving around the Invictus Games, a competition for sick and injured service personnel which the prince established in 2014.

The Duke and Duchess of Sussex will spend their first full day in Sydney by visiting the city's Taronga Zoo where they will meet native Australian wildlife, before travelling by boat to the Sydney Opera House to address fans.

A new royal baby, due in the northern hemisphere's Spring of next year, has boosted excitement surrounding the visit which will also include Fiji, Tonga and New Zealand later in the itinerary.

The Invictus Games will take place in Sydney from Oct. 20 to Oct. 28.