The singer posted a video of himself singing the song on social media, however, he put his own spin on the song.
"You're my, my, my, my... brother," he sang as he zoomed into brother Nick Jonas' head.
It's a beautiful work of art, really.
Some fans even thought it should be the official remix, instead of Shawn Mendes', since Shawn was sitting right next to John Mayer as he talked sh*t about it.
John was hosting his Current Mood Instagram Live talk show with Shawn as his guest star recently, where he took the opportunity to talk about Taylor's new song 'Lover' (which Shawn has already remixed).
John admitted that he loves the song and that he gets "a little chuckle" out of it because of the lyrics.
He was specifically talking about the lyrics: "We can leave the Christmas lights up till January", calling her "insane" because "everyone keeps their Christmas lights up until January."
"Normally I take my Christmas lights down on December 29th," he continues, sarcastically.
"So you don't like the song?" Shawn asked.
"No I love the song, I love your work on it" John continued, going on to remix the song himself as Shawn laughs.
His own version makes fun of Taylor's with the lyrics: "We can keep the Christmas lights up till January. And then about January 5th, we'll take the lights down. And then we’ll put 'em in a box and we’ll label that box Christmas Lights. Yeah, we'll put 'em in the attic until next December."
While some Tay Tay fans saw it as good fun, others were highly offended.
"John has no reason to bring her up unless to step up and support what’s happening right now. Which he isn’t," tweeted one user.
"They're trying so hard to be funny I have to laugh," wrote another.
For those who don't know, John and Taylor dated in 2009 for a hot minute when she was only 19-years-old. Fast-forward to their sudden breakup and Taylor released her seven-minute-long ballad 'Dear John' in 2010 that completely shunned him for using her.
As for Taylor and Joe, the pair dated in 2008 for a short few months. During this time, Joe broke Taylor's heart over a 27-second-long phone call. Taylor's song "Last Kiss" and "Forever and Always" were about her break up with Joe.
Now, the two are on good terms, with Taylor even apologising on Ellen DeGeneres' show about how she acted after their split.
Exes of the world, be a Joe... not a John.