According to reports, the couple had a heated argument over the phone this weekend and Crystal decided to pull the plug on their impending nuptials.
She moved out of the Playboy Mansion days before her wedding day.
“The wedding is off,” Hefner Tweeted. “Crystal has had a change of heart.”
The ceremony was to be held at the Playboy Mansion this Saturday. More than 300 people were expected to share their joy.
The marriage would have been the third for Hefner, who filed for divorce from his second wife Kimberly Conrad in 2008. He first wed Mildred Williams, whom he divorced in 1959.
Hefner and Crystal became engaged last Christmas.