Kate's pregnancy was pretty hush-hush. But a massive hint was dropped regarding the Royal baby

A notice posted outside a British hospital has triggered new speculations about Kate Middleton and Prince William's unborn third baby.

A "wet paint" notice added to the steps outside the Lindo Wing at St. Mary's Hospital has caught the attention of royal observers, as reported by All Cute All The Time.

The sign implies that pictures of the royal baby may soon be taken on the steps, just like when Kate gave birth to Prince George and Princess Charlotte.

Kate and William's third baby will most likely be born in the Lindo Wing of St. Mary's Hospital, just like the royal couple's older two babies.

The royal family has kept Kate's third pregnancy mostly in the dark. There has been no word about what the gender of the baby is or the baby's name.

The secretiveness even led to speculations that Kate and William may be surprising the world with twins.

The Duchess of Cambridge, who is due this month, April 2018, suffers from a rare pregnancy-related disease.

She is afflicted with hyperemesis gravidarum, a rare condition characterized by a type of nausea and vomiting that occurs only during pregnancy.

This is worse than the morning sickness and passive nausea commonly experienced by most pregnant women.

Kate has suffered from this during each of her three pregnancies.

She experienced severe nausea, fainting, extreme dizziness, and persistent vomiting. If not addressed, the symptoms can have serious implications.

Persistent vomiting can lead to severe dehydration for the mother and the child.

Kate's condition had concerned Prince William so much, especially during this latest pregnancy.

He had Kate stop her royal outings one month before her due date. Doctors had advised Kate to spend the next weeks getting as much rest as she can.

Kate and William, who have been married for almost seven years, are already parents to two children - Prince George and Princess Charlotte.