The 32-year-old striker shared the photo with his 11.6milllion Instagram followers…and it raised a few eyebrows.
The photograph was met with mixed responses from football fans, with one stating: “Wow. Barca…Rooney go to Barca.”
While a furious fan added: “Why you letting him wear that?”
Followed by: “His son prefers Barca to Everton.”
Despite being an avid Toffees fan, the eight-year-old signed for the Manchester United youth development squad last year.
However, it appears that Kai has always kept a place in his heart for Barcelona after meeting a handful of their biggest stars in 2015.
The Everton fanatic spent time with Lionel Messi, Luis Suarez, Neymar and former Manchester United ace Gerard Pique.
Rooney made a switch back to his beloved Goodison Park this summer, but the striker was concerned that Kai would ruin the move.
The retired England skipper told his Toffees mad son that he was considering a return to Everton, before panicking that he would spread the gossip on the playground.
Kai is a Toffees season ticket holder and can regularly be spotted in the crowd supporting his father.
The youngster is no stranger to the spotlight, having acted as a mascot with his father at several matches throughout his prolific career.
He has two brothers – Klay Anthony Rooney and Kit Joseph Rooney.