Prince William and Kate Middleton have confirmed their second child is due in April 2015.

The Duke and Duchess of Cambridge previously revealed Kate was pregnant again in September, but are yet to announce the sex of their unborn baby.

[related]Just like her first pregnancy with Prince George, the Duchess has been experiencing acute morning sickness and has been forced to cancel a number of engagements, with the palace now confirming her condition has improved.

She is now expected to join Wills on Tuesday (October 21) to welcome President of Singapore Tony Tan and his wife Mary.

A Kensington Palace spokesman said: "Their Royal Highnesses The Duke and Duchess of Cambridge are delighted to confirm they are expecting a baby in April 2015.

"The Duchess of Cambridge continues to be affected by Hyperemisis Gravidarum, but her condition is steadily improving."

Kate is also confirmed to attend the Wildlife Photographer of The Year 2014 Awards ceremony at the Natural History Museum, later on Tuesday.