The 26-year-old singer was spotted out and about in Australia on Thursday, dressed in skimpy overalls and a white top. While exiting the local clothing store Kookai, Swift flashed a smile and seemed to be in good spirits.
"Hurtful to me at this point that her and her team would go so far out of their way to try and make ME look bad at this stage though," Harris tweeted. "I figure if you're happy in your new relationship you should focus on that instead of trying to tear your ex bf down for something to do."
Swift initially heavily promoted "This Is What You Came For" when it was released in April, but after her split from Harris, she reportedly felt disrespected. A source told ET that "during their relationship, Taylor wrote the song, sat down at a piano and did a demo into her iPhone."
When she sent it to Harris, he apparently loved it. "They both went into a studio and did a full demo with Taylor on vocals and Calvin doing the beat," the source added. "They both knew the song would be a hit, but Taylor wrote it for Calvin and [they] both agreed it was a bad idea to let the world know they collaborated as a couple -- it would overshadow the song."