Harris spoke about her relationship with the Playboy mogul in an interview on The Howard Stern Show this week.
Hefner later told followers on his Twitter account that the interview was "crazy" and "didn't have much to do with reality", although later deleted the messages. However, he did reply to one follower who questioned which part of Harris's interview had been inaccurate, saying: "Crystal convinced me that she adored me. That was the first lie."
He has now posted on his feed: "Howard Stern would like me to respond to his interview with Crystal on his show tomorrow, but I don't want to throw her under the bus."
Harris has yet to comment on the interview.
Hefner popped the question to Harris on Christmas Day and the couple were scheduled to wed at the Playboy Mansion in June. However, Harris called off their engagement just days before the planned nuptials.
Hefner has since embarked on relationships with Playmates Anna Sophia Berglund and Shera Becherd, recently saying that he is in a "better place" with his new girlfriends.
> Crystal Harris: 'I'm still friends with ex-fiancé Hugh Hefner'
> Hugh Hefner 'dodged bullet by avoiding Crystal Harris marriage'
Watch Crystal Harris on The Howard Stern Show below (contains adult language):