Harris called off her engagement to the Playboy mogul just days before they were due to tie the knot at the Playboy Mansion in June.
Hefner has since moved on with Playboy Playmates Anna Sophia Berglund and Shera Bechard.
He wrote on his Twitter account this week: "I'm happy to be in a better place with new girlfriends Anna Sophia Berglund & Shera Bechard", adding to one follower that Bechard is a "great girlfriend" and a "classy lady".
Hefner had earlier responded on Twitter to a recent interview that Harris gave on The Howard Stern Show in which she discussed details of their sex life.
The 85-year-old told Twitter followers 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."
Hefner also posted a message clarifying his recent comments that he "dodged a bullet" by not marrying Harris, saying: "When I said, 'I missed a bullet' when Crystal left, I didn't mean I didn't love her. I meant I realised she really didn't love me."
Harris has yet to respond.
> Crystal Harris: 'I'm still friends with Hugh Hefner'
> Hugh Hefner: 'I truly didn't see Crystal Harris split coming'
Watch Hugh Hefner's recent appearance on Piers Morgan Tonight below: