During an American radio show, Crystal Harris revealed about his prowess in the bed, claiming he never turned her on.
She also claimed that sex with the 85-year-old lasted 'like two seconds' and was ultimately unsatisfying.
"Then I was just over it. I was like, 'Ahhh.' I was over it. I just like, walked away. I'm not turned on by Hef, sorry," the Daily Telegraph quoted her as telling on the 'Howard Stern Show'.
She also revealed they had only been intimate once, reports the Daily Mail.
"He doesn't really take off his clothes. I've never seen Hef naked," she told the show.
Hefner later responded on his official Twitter account, writing: "Crystal did a crazy interview with Howard Stern today that didn't have much to do with reality. Is she trying to impress a new boyfriend?"
He also added that he felt sorry for his ex-fiancee because she "seems lost".
Harris and Hefner announced their engagement in December 2010 but later called off their marriage just days before the ceremony was scheduled after Harris experienced a "change of heart".
