The Derry super bantamweight takes on Scottish champion Joe Ham for the vacant BBBoC Celtic title once held by Carl Frampton.
The fight plays out on the packed Mick Conlan Homecoming bill at the SSE Odyssey Arena and, while it may not be as heated or as long-running as the Jono Carroll feud, there has been an increasingly spicy build-up to the clash.
For McCullagh, the rivalry is one which is part created to help motivate himself as well as also being a response to some early trash-talk from the Glaswegian.
In an interview with Irish-Boxing.com back at the start of May, Ham [14(5)-0] labelled McCullagh ‘deluded’, angring White Chocolate.
Talk from the Scot has gone quiet in recent weeks but, as fight night approaches, McCullagh has become more outspoken, even coming up with a new nickname for his unbeaten foe.
“‘The pig’ nickname is just a bit of banter,” McCullagh explained before outlining the histroy of the mini rivalry.
“He was saying a few things, but he has gone very quiet and blocked me on social media as well.”
“I don’t know what he is trying with mind games and I hear he isn’t coming over for the press conference. As long as he is there on Friday for the weigh-in and fight night I don’t mind.”
“I don’t like him because I am going to box him for ten rounds although we will shake hands when my hand is raised. You can’t like someone you are fighting. He is going down.
“It is a great fight and fair play to him for taking it. We are both putting unbeaten records on the line and it makes for a very interesting fight.”
As well as being for the Celtic belt, their fight is an eliminator for the British title which Jazza Dickens and Martin Ward rematch for next month.
McCullagh, who trains alongside former Rigondeaux foe Dickens under Derry Mathews, is in no hurry for the British belt, preferring to focus on Ham.
The 27-year-old southpaw outlined how “there are few obstacles to get over first before I fight for the British title. Jazza Dickens is my team-mate and he is fighting for the British title so we may not fight each other.”
“We will cross that bridge when it comes to it, but the British title isn’t high on my priorities. I’m Irish at the end of the day.”