Just days after the pair spilt, Taylor was spotted in those now infamous pictures, looking cosy with Night Manager star Tom Hiddleston.
Hiddleston and Swift were caught kissing on the beach on Monday afternoon, while vacationing at the 26-year-old singer's multimillion-dollar home in Watch Hill, Rhode Island.
There was said to be "no drama" in their break-up, but Calvin Harris now reportedly believes that Taylor Swift cheated on him with Tom Hiddleston while they were still together. When asked to comment about this, Calvin Harris seemed to shrug it off saying, "It's all good, it's all good".
"You know what, it's like, when I find that person that is right for me, he'll be wonderful".
Hiddleston, 35, who is rumoured to be in the running for the role of James Bond, met Swift at The Met Ball in NY last month.
While at the time Calvin insisted the split was amicable, a source has now told E!
"He's pissed and feels betrayed by her", a source told TMZ, adding that Harris suspected something was up back in early May. "He knows that by hooking up with Taylor he will give himself the best opportunity in securing the part".
Though this was not confirmed if it was Calvin Harris, the report said that the photo was sent to a female executive while the DJ and the pop singer were still dating.
It looks like Harris isn't too happy with his ex, as he's already deleted their infamous breakup tweet and unfollowed Swift on Twitter.