Three's a charm... William and Catherine expecting again

Kensington Palace has announced that the Duke and Duchess of Cambridge are expecting their third child.

Prince William and the Duchess of Cambridge with their two children, Charlotte and George, pose for their first Christmas card as a family. Picture: @KensingtonRoyal.

CAPE TOWN - British royals Prince William and Catherine, the Duke and Duchess of Cambridge, have announced that they are expecting their third child.

Kensington Palace made the announcement in a statement on Monday.

According to the statement, Queen Elizabeth and members of both families are delighted with the news.

As was the case with her previous pregnancies Catherine is suffering from Hyperemisis Gravidarum which causes severe nausea, vomiting, electrolyte disturbance and weight loss, and this may lead to fewer royal engagements.

At present she is being cared for at the palace having cancelled her official engagements for Monday, the statement said.

The royal couple already has two children, Prince George (4) and Princess Charlotte (2).

Their third child would be fifth in line to the British throne. William, 35, is the eldest son of Prince Charles, the first in line to the throne, and a grandson of the queen.

Additional reporting by Reuters.