Gavin Henson claims Lions captain Brian O'Driscoll gouged him and pulled his hair in last year's Grand Slam decider between Wales and Ireland in Cardiff.
Henson says in his book that Ireland's skipper swore at him and called him "cocky" during Wales' 32-10 win.
The pair went on to become team-mates on the Lions tour, both picking up injuries that now have them sidelined.
But a simmering rivalry saw O'Driscoll criticise Henson for other comments in his book about the Lions tour.
The Irishman agreed with some of Henson's claims of tactical mistakes but was annoyed at statements over fellow players.
Henson wrote in his book "My Grand Slam Year" that some of his Lions team-mates seemed obsessed with the sound of their own voice.
The Wales and Ospreys star says that the gouging incident occurred early in the Ireland game after he took a heavy hit from O'Driscoll's centre partner Kevin Maggs.
"As I was on the ground, O'Driscoll came in and tried to 'jackal' me - a term we use to mean stealing the ball from your opponent on the ground," wrote Henson.
"But he also decided to pull my hair and tried to gouge my eye for good measure, saying 'How do you like that?'
"There was a real flash of anger in his eyes. It was intense.
"I still don't know what wound him up. It may have been something I'd said in the build-up."
Wales and Lions legend Barry John says that Henson may come to regret his revelations.
"It will be interesting to see the kind of reaction he gets when he bumps into fellow Lions in the Six Nations," John told the Wales on Sunday newspaper.
"Certain words will not be complimentary, and there might be the odd late tackle as well.
"Gavin has most definitely upset the applecart. He is young but should have been better advised."
Henson may even have provoked some of his Wales team-mates with comments in his book over foreign players representing the country.
"I honestly feel that three years of living in Wales does not make you Welsh," he wrote.
"Neither does having a Welsh grandfather if you were born and raised overseas."
South African Haldane Luscombe, New Zealander Sonny Parker and Australian Brent Cockbain have all played alongside Henson for Wales, while the latter two are team-mates at the Ospreys.
"Don't get me wrong, I love playing alongside these blokes and they've all proved massively important for the team," said Henson.
"It's the rule I'm talking about. I know of people who feel frustrated when they find their way blocked by these guys and I understand their feelings."