Ireland forward Iain Henderson admits he strongly dislikes facing Alun Wyn Jones, describing his former room-mate as an "absolute pest".
Henderson and fellow lock Wyn Jones are set to go head to head when Wales travel to Dublin for Friday evening's opening match of the inaugural Autumn Nations Cup.
The towering duo developed a close relationship during the 2017 British and Irish Lions tour to New Zealand.
Ulster captain Henderson has fond memories of that experience and concedes he would prefer to be lining up alongside the world's most-capped player than opposing him.
"I roomed with him on the Lions tour, he was a great lad, he was insightful in almost everything you chat to him about," Henderson said of 35-year-old Wyn Jones.
"I really don't like playing against him – it's probably one of his biggest talents. When players don't like playing against other players, it's almost a compliment to the type of player they are.
"He obviously adds a fair bit of oomph, if you like, to their pack.
"He's an absolute pest when it comes to breakdown and maul time, scrum time. The scrum generally looks a bit stronger when he's in behind there.
"In terms of the charisma he brings to the team, obviously he's captained them a lot and has a lot of leadership qualities, which you see coming out.
"Those are things that he brings and trying to negate that is difficult because he is a relatively resilient character who will continue to bring that irrespective of how the game's going for them.
"I don't enjoy playing against him for that sort of reason but the other challenge is an enjoyment of playing against him and it's great to catch up with him after the games too."
Henderson will provide a welcome boost to head coach Andy Farrell following a disappointing end to Ireland's Guinness Six Nations campaign.
The 28-year-old was a frustrated spectator for the final two fixtures of that competition due to suspension as their title aspirations slipped away with defeat in France.
His three-week ban was imposed after he was shown a red card for charging into a ruck and making contact with Ospreys back Dan Evans while playing for his province on October 10, a game in which Wales skipper Wyn Jones was on the opposing side.
Henderson, who is expected to be restored to his country's second row alongside James Ryan, admits he made a "stupid" error and has vowed to eradicate disciplinary issues.
"I think if anything it was probably clumsy," he said of the sending off.
"I joked about it afterwards that had it been maybe 50 minutes earlier in the game, I may have got in better body shape, a bit of fatigue kicked in there.
"It was stupid on my behalf, especially trying to close out a game like that – you don't want to be giving anything stupid away, so that's probably a frustration for me.
"I put my hands up and say it shouldn't have happened and again it's discipline, something I've had to work on a few times, so I will be looking to stamp that out of my game."
