The Royal Family announced on Sept. 8 that Kate Middleton and Prince William were expecting their second child via a statement on Twitter. After the Duchess of Cambridge was forced to cancel an event that day, Clarence House tweeted that Prince William and his wife were expecting.

"The Duke and Duchess of Cambridge are very pleased to announce that the Duchess of Cambridge is expecting their second child," a statement read. "The Queen and members of both families are delighted with the news that Their Royal Highnesses are expecting their second child."

Another statement on their website said that Middleton was back at Kensington Palace resting because she was suffering from acute morning sickness, also known as Hyperemesis Gravidarum. Reportedly she was being looked after by two family doctors.

A source close to the royal couple told US Weekly that Prince William and Middleton "very recently" discovered that she was pregnant again. The families weren't told of the news until this past weekend, shortly before Clarence House announced it publicly.

"William and Kate told their parents the news this weekend," the source said. "The Queen and Prince Philip were given the good news on Sunday morning. Everyone is delighted."

The source also said that the Duchess is only about eight weeks into the pregnancy, which makes her due date around March or April 2015. The couple's first child, Prince George, was born July 22 of last year.

As of Tuesday (Sept. 9) the source told US that Middleton's sickness hadn't improved much and she was still being looked at by doctors. Because she's been so sick, Middleton and Prince William decided to announce the pregnancy earlier than planned.

"Nausea and vomiting in pregnancy is really common, but hyperemenis gravidarum is a more specific disease characterized by prolonged nausea and vomiting, dehydration and at least 5% body weight loss." Dr. Shilpi Mehta-Lee told the Daily news.