Solicitors acting for former world champion Carl Frampton have confirmed that his former promoter, Barry McGuigan of Cyclone Promotions, has taken a legal action against him.
Frampton left the stable back in August, to join Matthew Macklin's MTK and Frank Warren of Queensberry.
Frampton also parted ways with trainer Shane McGuigan, who is Barry's son, and hired Jamie Moore.
The popular Irish fighter suffered his first career defeat earlier this year, when he traveled to Las Vegas and lost a twelve round decision in his rematch with Leo Santa Cruz at the MGM Grand.
Follow that defeat, there were rumors of tension behind the scenes between Frampton and McGuigan, and then eventually the boxer announced that he was a free agent - although McGuigan maintained that he had certain contractual rights with Frampton.
Frampton then signed a promotional deal with Warren, who is working with several potential opponents like Josh Warrington and IBF champion Lee Selby.
Frampton still has ties to the United States with an advisory deal with Al Haymon and Premier Boxing Champions.
The boxer has since returned to the ring, claiming a hard-fought points victory over Mexican Horacio Garcia in Belfast earlier this month. It was his first bout in his hpmetown in two years.
Frampton says he stunned by the legal move from McGuigan, but also noted that he intends to make it a real battle in the courts to defend his rights, with a counter-suit being planned.
A letter from Finucane Toner released on Sunday said their client, Frampton, was "deeply disappointed" by the move but would "defend his action rigorously and will counter claim on a number of grounds."
"Mr Frampton is confident that this process will vindicate his position and reputation, and looks forward to engaging fully in this process to present all aspects of this claim before the court," the statement concluded.