"I didn't even know she was there," he tells ET. "We didn't run into each other. We weren't even by each other."
Viall says he was invited to the runway show as a guest by a pal who is also friends with the designers. They took a photo before the show, sat down for the 10-minute presentation, went backstage to meet the designers and then left. There was no reunion with Dorfman, Viall maintains.
Even if she had been there, the businessman-turned-reality star tells ET that as far as he's concerned, the two are amicable. Viall says he would have said hello if he had seen Dorfman, but he doesn't even know if she saw him.
As for that cryptic tweet Viall posted on Sept. 13 that said, "I miss you so much it hurts sometimes," that was actually a reference to the sitcom Scrubs.
The line, which the 34-year-old later tweeted "really is the best line ever," is an inside joke with his hometown buddies. "It certainly had nothing to do with Andi or Kaitlyn [Bristowe] or any other girl," Viall explains.
Later Tuesday night, Viall was spotted with a girl, however, but she wasn’t Dorfman or Bristowe. He stepped out with model Kelly Thomas at a few NYFW events, including the Kenneth Cole store opening in Manhattan's Bowery neighborhood and OK Magazine's party at Haus nightclub.
But Viall denies that he and the gorgeous blonde are an item -- yet. He lives in Chicago, while Thomas' home base is New York, and the two have only known each other about a month. Both are signed with the Wilhelmina modeling agency, and Viall says that they met through the mutual connection. "It just kind of happened," he tells ET.
"She's not my girlfriend," he adds. "She's definitely a friend. She's an awesome girl."
Viall says that despite the amount of time he's spent in New York City recently, and the projects he's had in both the Big Apple and Los Angeles, he's not leaving Chicago anytime soon. "I'm open to the possibility, but nothing immediate," he says.