The pair are taking it slow
Taylor Swift "lit up" when she saw Harry Styles backstage at The X Factor in the US last week.
The 22-year-old singer and the One Direction heartthrob were seen holding hands at X Factor rehearsals in the US last week, and Taylor was said to be so happy to see him she was like "a puppy dog".
The source said: "They lit up when they saw each other. Taylor was a puppy dog."
After watching her rehearse and sitting by her mother, Harry then took the I Knew You Were Trouble singer to a backstage trailer in a particularly unusual manner - by carrying her.
The source added to Us Weekly magazine: "Harry picked her up and carried her to the trailer!"
Both have a colourful dating history, with Taylor previously being in relationships with actors Jake Gyllenhaal and Taylor Lautner and musician John Mayer, while Harry enjoyed a relationship with TV presenter Caroline Flack and was linked to singer Natalie Imbruglia.
However, a source said recently insisted Harry is determined to take things slowly with Taylor.
The source revealed: "Taylor and Harry have been quietly seeing each other again. When Taylor dates someone she jumps in full force, but Harry is being a little more cautious this time around.
"Taylor is a hopeless romantic, so she's really hoping it works out with Harry. Harry's being really sweet with her right now and careful not to hurt her."