The True Blood actor was reportedly seen with the actress at the premiere of his latest film That's My Boy earlier this week.
However, he stated that he only spoke to her for a brief moment during the evening.
"There is 100% zero truth to that," he said when asked about Demi Moore by Ryan Seacrest.
"I met her once at a premiere and I maybe talked to her for three minutes."
He added that he only spoke to her because she once starred in a movie about a stripper, which the actor will also soon be doing in Magic Mike.
"She was in Striptease, so I was like, 'Hey, you played a stripper! I'm playing a stripper'.
"We kind of had a three-minute conversation about exchanging stripping notes, and that was it."
Joe Manganiello currently stars in HBO's True Blood, which airs on Sunday nights on the cable network.
He will next be seen in Magic Mike, which opens in the US on June 29 and July 11 in the UK.
Watch the trailer for Magic Mike below: