William and Kate's new baby will be fifth in line to the throne - pushing their uncle Harry into sixth place.
Harry said he was "very, very happy" for his brother and sister-in-law, telling journalists "it's fantastic."
Asked how Kate was doing, he replied: "I haven't seen her in a while, but I think she's okay."
Whether the new little royal is a prince or princess, the 2013 shake-up of royal succession to remove male bias means the baby will be behind both brother George and sister Charlotte, as well as their father and grandfather.
![William and Kate have announced they are expecting a third child. Photo / Getty Images](https://www.nzherald.co.nz/resizer/v2/DEB72DOCHAD22GVFRJ6OK6J5QE.jpg?auth=90835bb62a3f50d9c1a019ec08b013b017bd5b679561e49a908764c439e25c28&width=16&height=11&quality=70&smart=true)