"How would she have time for that? Is it me?! Who came up with that story?" Harrison askedUs Weekly.
The Bachelorette host is definitely not the person dating Bristowe, but he's certain no one outside of the show is either.
"No, I don't think she had a secret boyfriend," Harrison said with a laugh.
In addition to Bristowe, Britt Nilsson is also in the running to become the reality dating competition's new leading lady. Both women competed for Chris' Soules heart on his The Bachelor edition, and this marks the first time two women will both serve as the franchise's Bachelorette to start out with.
However, the male suitors will end up selecting either Bristowe or Nilsson as the show's official star. It remains unclear what will happen to the rejected woman.
Harrison assured Us that Season 11 of The Bachelorette, which will premiere May 18 on ABC, has been "going great" so far.
"I think we couldn't go wrong with both of the girls, both very different," Harrison explained.
"Britt's emotional and beautiful, and Kaitlyn's beautiful and funny in a more sarcastic, bust your chops way. Two very different shows and it's going to be great. And a really great group of guys too. It's going to be a really good show."
On another note, Harrison sat in the audience when Soules took the Dancing with the Stars stage with his pro partner Witney Carson for the first time last week. Harrison admitted he was surprised to see how well Soules performed in the premiere.
"He absolutely kicked ass! I had seen some video -- he showed me some secret video earlier and I said, 'Well you're not terrible!' But I really didn't think he'd be that good," Harrison confessed.
"Even [Soules' fiancee] Whitney Bischoff was like, 'Wow! look at him!' The best moment was sitting between Whitney and Chris' mom -- she was crying, she was pinching me, she was so excited! It was really cool."