And now Kensington Palace have announced officially that yes, Duchess Catherine and Prince William, both 35, are expecting their third child together.
In a statement released on Monday morning UK time, the palace said the Duchess was experiencing severe morning sickness and will be missing out on her latest engagement as a result.
The magazine exclusively revealed that Kate was rushed to King Edward VII Hospital in Marylebone, London, at the end of last month, sparking a flurry of speculation she was pregnant.
"The Duke and Duchess of Cambridge are very pleased to announce that The Duchess of Cambridge is expecting their third child," the palace said.
"The Queen and members of both families are delighted with the news."
"As with her previous two pregnancies, The Duchess is suffering from Hyperemesis Gravidarum. Her royal highness will no longer carry out her planned engagement at the Hornsey Road Children's Centre in London today."
It concluded: "The Duchess is being cared for at Kensington Palace."
The proud parents already share four-year-old son Prince George, who starts school this week, and two-year-old Princess Charlotte.
"Kate's been spending much of her time in bed - her energy levels have been very low over the last couple of weeks," the source says.
"But she's ecstatic to be expecting baby number three - this is everything she's always wished for."
Relive the wonderful moment the Palace announced Kate and William were expecting their first child in the video player below!
Prince William and Duchess Catherine are delighted to be having three children.
Kate herself is one of three kids and has often spoken of the joys of having loving siblings around.
Despite their royal status, the Duke and Duchess of Cambridge are determined to give their growing family the most normal upbringing possible.
"We hope to encourage George and Charlotte to speak about their feelings, and to give them the tools and sensitivity to be supportive peers to their friends as they get older. We know there is no shame in a young child struggling with their emotions or suffering from a mental illness," Catherine has previously said of her approach to parenting.
“Stability at home is so important to me. I want to bring up my children in a happy, stable, secure world, and that is so important to both of us as parents," William explained to GQ earlier in the year.
“I want George to grow up in a real, living environment. I don’t want him growing up behind palace walls, he has to be out there.”
The new Prince or Princess will be fifth in line to the British Throne, bumping Uncle Harry to number six.
Congratulations again to the soon-to-be family-of-five!
For more exciting and exclusive details on Kate's third pregnancy, and for the first beautiful bump pics, get the latest issue of Woman's Day - on sale now!