Kate Middleton and Prince William
Kate Middleton's due-date is expected to be around April.Getty

Kate Middleton is around 10 weeks pregnant and the Royal Family is all set to welcome Prince George's sibling somewhere around April next year, reports OK! Magazine.

"They are so excited that George will be getting a younger brother or sister next April and Kate's just bravely fighting through this unwell stage under the guidance of palace doctors," a source told E! News.

However, there has been no official word from the palace on her due date.

Meanwhile, there is a speculation that she might be carrying twins.

A palace source told the National Enquirer (via celebdirtylaundry.com): "An ultrasound test performed around the six-week mark of her pregnancy indicated the presence of two heartbeats! If she is pregnant with twins, this may make her nausea more severe. The major danger of carrying twins is premature delivery. Other possible complications include hypertension and pre-eclampsia."

According to Kensington Palace, Kate recently dropped out of her first solo royal tour to Malta due to her continued morning sickness.

"Her Royal Highness continues to suffer from the effects of Hyperemesis Gravidarum. The decision not to visit was taken by the Duke and Duchess on the advice of the Duchess's doctors," a statement from the palace read.