The double-gold Olympic swimming medallist, 27, fought with Luke Greenbank, 25, after apparently slapping him on the bottom and making a ‘cocky quip’.
Anna Hopkin, 27, an Olympic champion herself, has been in a relationship with Mr Greenback for more than two years, having previously been in a couple with Peaty, who is now seeing Holly Ramsay, the daughter of TV chef Gordon.
A fight is said to have broken out at a Team GB swimming training camp in Loughborough last Friday.
Witnesses claimed that it kicked off when Peaty cracked a joke to Greenback and then hit him on the rump. A fight broke out that left Peaty needing treatment for a facial injury.
The Sun has claimed that the brawl, described as ‘total carnage’, did involve a jibe by Peaty about his ex-girlfriend.
Adam Peaty, pictured with his girlfriend Holly Ramsay at Silverstone in July, has reportedly received stitches for a facial injury after being involved in a fight with a Team GB swimming mate
Luke Greenbank, pictured with his girlfriend Olympic gold medallist Anna Hopkin, was apparently ribbed by Peaty who also reportedly slapped him on the bottom
Peaty (second from left) was reportedly hurt by his Team GB team-mate Luke Greenbank (far left)
Anna Hopkin (pictured) was previously in a relationship with Peaty before the pair stopped seeing each other. She has since been partnered with Greenbank for two years
A source told The Sun: ‘It was absolute carnage. Peaty was being cocky and made a joke at Greenbank’s expense, before touching his backside. But his actions touched a real nerve for Greenbank and it got very heated.
‘Peaty was left with a bloody face and needing treatment’.
Team GB coaching staff are said to have treated Peaty afterwards.
‘Those around them persuaded Peaty and Greenbank to shake hands and put the fight behind them’, the insider added.
Peaty split from Eiri Munro, mum to his two-year-old son George, last August and is now seeing chef Gordon Ramsay’s daughter Holly.
The 28-year-old has won eight world championships along with his Olympic titles and is widely hailed as the best breaststroke swimmer in history.
Greenbank and Peaty has previously competed alongside each other during Team GB relay races and even won silver in the 100m medley at the Tokyo Olympics.
Peaty is widely regarded as the best breaststroke competitor in the history of the sport
Peaty (second from left) apparently made a comment to Greenbank about his partner Anna Hopkin (far right)
Greenbank (pictured) reportedly retaliated to Peaty’s comment about his girlfriend
Peaty previously took time away from swimming in March as he attempted to focus on his mental health and wellbeing.
Both Holly Ramsay and Adam have had struggles with mental health and alcohol addiction.
In April, Adam pulled out of the British Swimming Championships, and said: ‘A good friend of mine said a gold medal is the coldest thing you will ever wear… because you think it will fix all of your problems [and] it will not.’
In December, Holly celebrated two years of sobriety, having previously hit ‘rock bottom’. She also set up 21 & Over, a podcast for people suffering from anxiety.
Adam has a three-year-old son, George, with his ex- girlfriend Eiri Munro. The couple split up last August as he apologised for letting down her and their son.
He said at the time that the couple had decided to go ‘their separate ways’ but that their son George, who is two next month, remained their ‘priority’.
Announcing the news via social media, Adam wrote: ‘Eiri and George, I’m sorry for letting you down. My only interest is for the well-being of our family at this difficult time.’