Taylor and Harry dated from 2012 to 2013, and the original "1989" album came out in 2014, so the timeline's already telling ... but the lyrics are even a bigger clue, according to fans -- talking about a time her ex "lost control," resulting in "red blood" and "white snow."
Fans have started to connect the dots ... saying Taylor claimed in 2014 she got into a snowmobile accident with an ex. At the time, Harry was spotted with a bandage on his chin.
She sang about the accident in the track "Out of the Woods," also from 2014 -- “Remember when you hit the brakes too soon/Twenty stitches in a hospital room/When you started crying, baby, I did too.”
That's not all ... the new song talks about Taylor wearing a "blue dress on a boat," and a pic from 2013 showed her wearing exactly that while taking a boat ride away from the Virgin Islands, where she was vacationing with Harry.