Defiant John Hartson insists he now calls the Old Firm clash with Glasgow derby because "he is Celtic" in an exchange with Craig Moore.
The rivalry in Glasgow is reaching boiling point ahead of Sunday's top of the Premiership clash as Ange Postecoglou's leaders face champions Rangers.
With tensions rising between the two sides, even the name of the derby clash has added fuel to the fire.
Former Celtic striker Scott McDonald started the debate again as he correct himself during an interview after initially referring to the clash as the "Old Firm".
He then switched to calling it the Glasgow derby, which saw an angry caller asking for former Rangers star Craig Moore and Hartson to give their take on the Go Radio Football Show.
Moore said: "It's Old Firm derby for me all day long. I've always seen it as the Old Firm derby. Everyone has got their own take on it.
"Since coming back (to Scotland) 18 months ago, we've done a bit pre-show and it's the Old Firm. That's the title decider that's coming on Sunday. That's the Old Firm."
However, Hartson disagreed stating: "Well, the last few times (I've been on) I've said Celtic/Rangers.
"I think there's a view that a lot of Celtic fans say now it's the Glasgow derby, and they will have to come on here and explain why they say that.
"If it's Rangers you would say Rangers and Celtic. I've been saying that because a lot of the Celtic fans don't like to say the Old Firm.
"As you know I am Celtic, I'm not Rangers. Listen, the Old Firm, it's always been called the Old Firm, and the Celtic fans have always decided to call it the Glasgow derby.
'They can come on and explain why."
When challenged on if he was snubbing a big selling point of the derby by not calling it the Old Firm, he added: "To some people yes, but not to others."
