The young celebrities, who co-star in the Dr Seuss film The Lorax, were said to be "deep in conversation and very giggly" while dining at Los Angeles Italian restaurant Place earlier this month.
However, a source told Us Weekly that the meal was purely platonic and that nothing is going on between Swift and Efron.
"They were in LA doing press stuff together, and after they were done, they decided to grab dinner," the insider explained. "They have been friends a long time."
Another source added: "Taylor thinks Zac's cute... [but] they are on totally different wavelengths."
Swift recently revealed that her new album will deal with 'earth-shattering heartbreak' stemming from a previous break-up.
Watch the trailer for Dr Seuss's The Lorax below: