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Playboy founder Hugh Hefner (L) and his fiancee Crystal Harris celebrate Hefner's 85th birthday at the Playboy Club at the Palms Casino Resort in April.
Hugh Hefner confirmed via Twitter Tuesday that marriage plans have been canceled.
Hefner, 85, and Playmate Crystal Harris, 25, had planned to wed Sunday. Hefner tweeted Tuesday, "The wedding is off. Crystal has had a change of heart."
Harris, a former La Jolla High School student, studied psychology at San Diego State Unversity.
The marriage would have been Hefner's third. He filed for divorce from the his second wife, Kimberly Conrad, in 2009.
He was previously married to Mildred Williams. The couple divorced in 1959.
People magazine reported that about 300 people had been invited to the wedding at Hefner's Holmby Hills mansion.
"I heard the very sad news this morning," Harris' manager told Access Hollywood. "All I can say is that from what I’ve been told is that the breakup was amicable. Crystal and Hef will remain friends."