The "Style" singer, 25, and the "Blame" producer, 31, attended Kenny Chesney's concert in Nashville Thursday. According to Taste of Country's Twitter account, they were "getting snuggly" during the show.
Neither Swift nor Harris has confirmed the romance rumors.
That being said, pictures show Harris standing behind Swift with his arms wrapped around her waist, and an eyewitness tells E! News, "They were dancing to a lot of songs! 'There Goes My Life,' 'I Go Back,' it was a lot of songs," adding, "I didn't see them kissing but his arms were around her. They sure were cute together! They both were dancing, looked like they were having a great time."
When Swift joined Chesney on stage to sing "Big Star," Harris cheered for the two.
Thursday's outing came just hours after pictures surfaced of the two shopping at Whole Foods on Wednesday (in matching outfits). Earlier this month, Swift attended one of Harris' concerts in Las Vegas—and that was after the EDM artist told Capital FM that she "looks lovely" but is not his "type."
If their recent outings are any indication, Swift has clearly changed Harris' mind.
Taylor and Calvin Harris. (Be cool) pic.twitter.com/v4ynFWiBwU— TaylorTunes (@TaylorTunes) March 27, 2015
Harris was most recently linked to model Aarika Wolf; they broke up in February.
Swift hasn't been in a serious relationship since she broke up with One Direction's Harry Styles in January 2013. Prior to that, she romanced Jake Gyllenhaal, Joe Jonas, Conor Kennedy, Taylor Lautner and John Mayer. When the "Blank Space" singer was promoting her album 1989 last year, Swift told E! News she hadn't sworn off dating, but she was being "very protective" of her happiness. "I found a place in my life that feels really great and I'm not willing to compromise that for just anyone, and so, you can paraphrase that all you want into something very extreme, but they make what I say extreme no matter what I say. I'm really happy about the fact that being single doesn't feel like being alone," she said. "I have love in my life, I just don't have a relationship, and that feels really natural right now."
Around the same time, Swift also spoke to People about her single status.
"I'm not going to compromise the happiness and independence that I've found for just anybody. The idea of a date gives me a partial panic attack!" the seven-time Grammy Award winner said. "It includes 40 paparazzi cameras shooting through windows at us, and that's not relaxing or alluring for me. That makes me want to crawl under the couch and hide! But I'm fine! I have two cats. That's all I need."
"It would take an astonishing human for me to even consider getting back into a relationship. It would take something really, really, really, really different—a kind of a one-in-a-million person for me to face all that. I don't have any kid of idea who I'd want to be with, because I don't have any pieces missing from my life right now. I'm not looking for anything to complete," she said. "I think that's a nice place to be."
Perhaps Harris is the "astonishing human" Swift was hoping to meet!
—Additional reporting by Ari Forer