We're not too sure about this logic...

Last week, Kensington Palace confirmed that the third royal baby is on the way after Kate Middleton was forced to cancel a public appearance at a children's centre in London. As with her previous two pregnancies, the Duchess is again suffering from Hyperemesis Gravidarum, an extreme form of morning sickness which is characterised by incessant nausea and vomiting. The next day, Prince William spoke at a Mental Health and Policing Conference in Oxford where he was congratulated by the officers in attendance.

HRH gives a speech on the issue of mental health and the impact it has on policing pic.twitter.com/aSQve22bRU

— Kensington Palace (@KensingtonRoyal) September 5, 2017

Commenting on the "very good news", his first thought was of his wife and he updated well-wishers on her health but now, it's been suggested that his words may have hinted at Kate's due date. According to E! Online, he said:

"We need Catherine to get over this first bit and then we can start celebrating. It's always a bit anxious to start with, but she's well". "There's not much sleep going on at the moment".

There's a theory that the Duke of Cambridge's comment that they could start celebrating "this week" meant that Kate had reached the 12-week mark, which is the stage that many couples decide to announce the happy news. If this is true and it's very unlikely that the couple will confirm the actual date, then Kate would be due to have her third child in March. We'll take this theory with a pinch of salt!