"Demi is a close friend, a dear friend," Nick shared, according to E! News. "We've become close and I care very much about her."
There was also a recent post made on Reddit by an anonymous poster claiming Nick and Demi are more than just friends.
Nick reportedly believes the anonymous poster lives in his building in Los Angeles, CA.
"I've been violated. We've talked about Reddit before on the show," Nick said on his podcast.
"I've tried not to go on. I haven't been on it in some time... But I do have friends and an occasional fan who reads and they brought it to my attention that I now live with someone in my intimate building -- it's a building in Venice and there are six units -- and I live with someone whose been spying on me."
The alleged violator apparently spotted Demi visiting Nick's home, but Nick didn't dispute that claim.
"Demi has in fact been to my place, as sometimes friends do go to each other's places," Nick reasoned, adding that he has an idea whom the spy might be and it's a female.
"If you're 'Venice Lurker' please stop spying on me and invading my privacy."
There was previous speculation Nick had once dated actress January Jones, and more recently, actress Rachel Bilson, among other women.
However, Nick has insisted he's single, much like Demi, who announced her split from fiancee Kristian Haggerty on October 31.
Demi and Kristian got engaged on the season finale of Bachelor in Paradise's sixth season after Demi failed to win Colton Underwood's heart on The Bachelor's 23rd season.
When Demi publicly came out as "fluid" in terms of her sexual preference towards the beginning of Bachelor in Paradise's latest season, she revealed she's attracted to an individual and who that person is rather than a particular gender.