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Since their marriage in April 2011, watched by an estimated two billion people around the globe, speculation has turned to when the second-in-line to the throne and his bride would start a family.
"Realistically, there is not going to be time for a baby and they have said they are in no hurry," an unnamed royal source told The Mail On Sunday.
"There is no urgent need for an heir - we already have two.
"William and Kate want to take things in their own good time."
RAF helicopter pilot William, 30, leaves for a six-week tour of duty in the Falkland Islands in February, when Catherine, 30, is expected to begin her charity work, making official and private visits as patron to a number of British organisations.
"It will be a good distraction for her and take her mind off worrying about William," the source said of Catherine's new role.
"At the moment, starting a family is definitely on the back burner."
Later in the year the couple will visit Singapore, Malaysia and the Solomon Islands as part of the royal family's global tour to celebrate the Queen's 60th year on the throne, which will be marked amid much pomp and ceremony in London in early June.