Middleton, 29, and Jackson, 35, have been dating at least six months.
Rumors began swirling during the weekend that the couple are making wedding plans, however, UsMagazine.com cited unnamed sources as saying the buzz isn't true.
Middleton's sister Kate married Prince William in April 2011 and gave birth to their first child, Prince George, in July.
Couple mistakenly served bag of cash at McDonald's drive-thru
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