It all started last week when the 29-year-old singer appeared on The Tonight Show. Host Jimmy Fallon played a clip of the "Lover" star recovering from the procedure and becoming a tad distressed over the selection of her post-surgery snack.
"That wasn't the one I wanted," a groggy Taylor said after peeling back a banana.
Her mother Andrea Swift, who reportedly shot and shared the footage, then consoled the artist before ushering her back into bed for some rest and relaxation.
After seeing the video, Justin did his own spoof. In an Instagram Live video, the 25-year-old crooner can be heard imitating Taylor and yelling "it's not the banana that I wanted" in his kitchen.
While his wife, Hailey Bieber, said the bit was "so funny," not all of Swift's fans were laughing.
This wasn't the first time the celebrities have been accused of having some bad blood. As fans will recall, Taylor accused Justin's manager, Scooter Braun, of "manipulative bullying" after his company purchased her former record label last summer.
"Like when Kim Kardashian orchestrated an illegally recorded snippet of a phone call to be leaked and then Scooter got his two clients together to bully me online about it," she wrote in a Tumblr post alongside a photo of Scooter FaceTiming with Justin and Kanye West.
Justin later defended Scooter on social media.
Still, they aren't the only celebrities to make headlines over feud rumors. To look back at more stars' drama, check out the gallery.