Demi Moore has denied making comments about boyfriend Ashton Kutcher being too fast in the sack.

"I had a conversation with Demi Moore about both of us dating younger men," fashion designer Cynthia Rowley told the New York Daily News.

"We were talking about the pros and cons of all that. ... We talked about sex. It wasn't that graphic - it was just that sometimes it's faster with younger guys."

Moore now denies the chat ever happened, however. A rep for the actress said: "She has no recollection of ever having this conversation with Cynthia Rowley, and she would never discuss something as intimate as that with a person she barely knows."