The father of former boxing champion Ricky Hatton was arrested for attacking his son the day before he announced his comeback, police sources said.
It is understood that Hatton, 33, had to protect himself after his dad Ray, 61, attacked him during a heated row in the car park outside his Manchester gym.
Police were called and Hatton senior was arrested and cautioned.
A spokesman for Greater Manchester Police said: "Shortly before 11.45am on Thursday, police received reports that there had been a fight involving two men outside a health and fitness club on Market Street, Hyde.
"A 33-year-old man was assaulted by a 61-year-old man, who was arrested on suspicion of common assault and subsequently given a police caution.
"The 33-year-old man was not injured in the incident."
Yesterday Hatton - nicknamed The Hitman - said he would strive to earn the nation's pride again after seeing his life "turn to mush" in the three years since he last fought.
The Hyde fighter has suffered a series of well-publicised issues in his private life since his last fight saw him knocked out by Manny Pacquiao in their IBO light-welterweight title fight in Las Vegas.
Hatton insisted he did not want to see those demons tarnish his legacy in the sport, with another world title belt in his sights.
The fighter was the subject of allegations of cocaine abuse two years ago and within days he was admitted to a rehabilitation facility.
Drink and depression were major issues for Hatton at the time.
"I don't want people telling my kids that I blew it," Hatton said as it was announced he would return to the ring on November 24 in Manchester.
"I want my kids to be able to say, 'He was a world champion, he had his problems, but my did he bounce back'.
"I want people to be proud of me again. I want British sport, my kids and my fans and my friends to be proud of me."