Someone unearthed a tweet from him from June 2012 professing his love for Rangers' fierce Glasgow rivals Celtic and this forced the 33-year-old to provide an explanation for those comments after putting pen to a two-year deal at Ibrox.
Barton, who played an influential role in Burnley's promotion to the Premier League last season, has a simple explanation for his comments: that he talks a lot on social media!
"If you follow my Twitter feed, I have probably offended the whole world at some point. So people can delve into it and find what they want to set an agenda against me. Such is the nature of someone who has opinions, like I do.
"In a football family in a football hotbed, you are forced to take sides. When Madrid play Barca. When Inter Milan and AC Milan play. Who are you supporting? You have to pick one! And obviously the world stops to watch Celtic and Rangers and you are forced to pick sides.
"Being Joseph Anthony, and my grandmother being Roman Catholic, and going to St Agnes junior school and St Thomas-a-Beckett, I didn't have pretty much anywhere to go! That is pretty much who you are going to support!
"But I don't think anybody will be under any illusions about who I will support once I pull on the Rangers jersey.
"It may sound strange to say this but as a footballer you stop supporting. I was an Evertonian who grew up supporting Everton and Everton released me at 14. I was absolutely devastated. I went home crying my eyes out, having learned the harsh realities of being a professional footballer.