Alun Wyn Jones has warned his Welsh team-mates of the dangers posed by his Lions captain Paul O'Connell.
Jones, who made six appearances during the 2009 tour of South Africa, packed down alongside O'Connell in the Lions boiler-house during the first Test.
But the Lions second-row partners will come head to head when Wales welcome Ireland to the Millennium Stadium in their penultimate RBS 6 Nations encounter.
Ireland talisman, O'Connell, was plagued by a groin injury following last season's Championship and received a four-week suspension after being red-carded in his comeback versus the Ospreys.
But after struggling to get to his feet, Jones reckons his old pal is nearing a return to his barn-storming best.
"His groin problem was probably one of the biggest injuries he's had and it set him back for quite a while," said the Ospreys lock.
"He came back from his injury, then he had another spell out through suspension.
"People said he struggled early on. But, after coming back from a long lay-off, you are going to struggle. Anybody would. There's a big difference between training fitness and match fitness.
"But he has got his match fitness back now. Against Scotland, he was coming to the fore a lot more and was his old self.
"Having played with him for the Lions, I know he's a great team man. That's the one attribute that really sticks out.
"I'm sure he's back to where he was almost and that will really add to the Irish pack.
"He will look to rule the roost in the lineout for them again now he is back."
History would say the odds are stacked against a Welsh victory. Since 1983 the men in red have only once triumphed over Ireland in Cardiff. That victory came in 2005 as Wales clinched their first Grand Slam in 27 years.
"We've only won one of the last 13 encounters at home, or something stupid like that, so there's a bit of a gap to catch up on," added Jones.
"Ireland's our last home game before the World Cup warm-ups.
"So we've got to really send a flare up to the fans and show them how serious we are moving forward.
"Both sides are in the same place really I think. We are getting the wins, but we both know we can play better.
"It's either going to be an absolute thriller or an attritional affair. I can't tell you which until after the game."