The singers split earlier this year and have been engaged in a public war of words ever since. Swift claimed that Jonas dumped her in a 27-second phone call, while Jonas said it was Swift who hung up on him. Swift has also accused Jonas of cheating on her with actress Camillia Belle.
The former couple will share the stage when they perform at ABC's Dick Clark's New Year's Rockin' Eve gig in Times Square at the end of the month.
Fergie and Kelly Pickler will also be appearing at the event.