Premier League footballer Joey Barton says he was "sucker punched" in the head during a fight outside a nightclub.
The controversial Queens Park Rangers midfielder, 29, was involved in an early-hours altercation with two men while on a night out with his girlfriend in Liverpool city centre.
Barton, who has become well-known for his opinionated Twitter outbursts, confirmed the attack, which happened outside Garlands nightclub.
He tweeted: "I got sucker punched in the back of the head.
"Not injured as reported just a small bruise on rear of head/ear.
"I've had worse. Life goes on! Thanks for the concern. Have a good day people."
Later he tweeted: "Not planning on pressing charges as it's not that serious. The police have also got better things to do with their time.
"Can I just say a public thanks to the police last night as they were and have been today brilliant."
A picture of the incident, apparently showing a shirtless Barton being held back by police and a woman, appeared on the site earlier.
The Liverpool-born footballer is under investigation by QPR after he was given a 12-match ban by the Football Association.
He was banned by English football's governing body after being sent off during QPR's defeat at Manchester City on the final day of Premier League season.
During the match, he elbowed one Manchester City player, kicked out at a second and attempted to headbutt a third.
In a statement, QPR spokesman Ian Taylor said: "Barton was on his way home from a night out with his girlfriend when two men sang offensive chants and then proceeded to hit the QPR midfielder."
Merseyside Police said two 21-year-old men from the Old Swan area of Liverpool were arrested on suspicion of a public order offence and were being held in police custody.
A spokeswoman for the force said: "Police were called to Eberle Street in Liverpool city centre at 5.30am this morning following reports of an altercation.
"On arrival, officers found a 29-year-old man who had sustained injuries to his face. The man left the scene voluntarily."
News of the fight was widely commented on by Twitter users, with the words Joey Barton and Garlands trending throughout the day.
JoshGore-11, who claimed to have been at the scene, said Barton had "looked in a bad way" after the fight.
Barton has a long history of controversy, both on and off the pitch.
In 2008, he was given a six-month jail term after admitting assault and affray during an incident in Liverpool.
Here, we detail some of the other incidents that have been bad news for Barton.
February - Barton red-carded for the first time in Manchester City's FA Cup fourth-round tie at Tottenham, for two bookable offences.
April - Barton storms out of Eastlands before kick-off after being axed from team to face Southampton.
July - Criticised by City manager Kevin Keegan for causing mass brawl in a pre-season friendly at Doncaster.
December - Stubs lit cigar in the eye of young team-mate Jamie Tandy during City's Christmas party. Fined six weeks' wages by the club. Forced to pay four weeks' salary - approximately £60,000 - immediately, with a further two weeks suspended for a year. Tandy later sued Barton, winning £65,000 in damages.
July - Involved in altercation with a 15-year-old Everton fan at City's team hotel in Bangkok during a pre-season tour. Fined eight weeks' wages by City after being found guilty of gross misconduct.
September - Drops his shorts in the direction of Everton fans following City's 1-1 draw at Goodison Park.
December - Shown the second red card of his career - this time a straight red - for a two-footed lunge on Abdoulaye Faye in City's 2-0 home defeat to Bolton.
May - Suspended by City after training-ground altercation with Ousmane Dabo, which leaves his team-mate needing hospital treatment. Charged with assault, and on July 1 2008 receives a four-month suspended jail sentence. Also punished by FA with a 12-match ban - six matches of which are suspended and a £25,000 fine.
December 27 - Arrested in Liverpool city centre after a late-night incident and later charged with common assault and affray. Remanded in custody and misses Newcastle's New Year fixtures, being released on January 3.
May 20 - Jailed for six months after admitting common assault and affray in relation to the 27 December incident.
May 3 - Sent off against Liverpool for late challenge on Xabi Alonso. After a reported dressing-room bust-up with manager Alan Shearer following the game, Barton was suspended from the club for the rest of the season.
November 10 - Punches Blackburn winger Morten Gamst Pedersen during a 2-1 defeat for Newcastle at St James' Park. Accepts an FA charge and is banned for three games.
August 1 - Newcastle transfer-list Barton after a series of Twitter comments criticising the club, making him available on a free transfer. He joins QPR on August 26.
January 2 - Scores but is then sent off as QPR lose 2-1 at home to Norwich in the Premier League.
January 26 - Unleashes an online tirade against the Football Association, labelling them an "Orwellian organisation" in need of a "drastic shake-up".
May 13 - Sent off for elbowing Carlos Tevez on the final day of the season at Manchester City. Knees Sergio Aguero, sending the striker to the ground, and attempts to headbutt Vincent Kompany before being ushered off the field.
May 14 - In the wake of his final day red card, launches an expletive-laden Twitter attack on Shearer, his former manager at Newcastle and current Match of the Day pundit, before turning on the programme's presenter, Gary Lineker, saying: "back under your stone you odious little toad..."
May 23 - Banned for 12 matches and fined £75,000 after being charged with two acts of violent conduct against Aguero and Kompany. He accepted the former, but denied the later and requested a personal hearing, where the verdict went against him.