The South African-born forward was one of his province's standout players as they secured the 2022/23 United Rugby Championship title.

Top quality tighthead locks are few and far between, with Kleyn particularly outstanding in the tighter exchanges.

He has the size to dominate the contact area and also make it over gain line at close quarters, while his technical expertise sees him excel at lineout and maul.

Many expected him to be called into the Irishmen's wider training squad but he was a surprise omission from the 42-man group.

That allowed the Springboks to pounce, who took advantage of World Rugby's change in eligibility laws to bring him back into the fold.

Kleyn earned five caps for Ireland in 2019 after qualifying on residency but was able to switch allegiance for the second time after his stand down period exceeded the required three years.

He has since made his Boks debut and will earn his second cap for the national team against Argentina this weekend.

O'Connell revealed that the lock "was very close" to selection for the Irish World Cup squad but that the coaches decided that he was behind the others in the pecking order.

"He's very experienced now, he has experienced different coaching staffs with Munster. He was part of a really successful Munster team this year and he does what he does really well," the forwards coach said.

"He's an excellent mauler, excellent maul defender. I think his ball-handling and his defence has improved massively now in the last few years.

"He looked very comfortable playing for Munster. The forwards were asked a little bit more of them this year and he was very comfortable.

"It was close, it was tight, I suppose some of the guys we had in the squad already, we felt we'd invested a good bit in them already, they were a little bit younger, they were quite big men as well in their own right.

"He went away and he's entitled to go for what he went for and I wish him all the best."

Someone who knows Kleyn well and the value he brings to a side is Munster team-mate Tadhg Beirne.

"I gave him a few texts here and there, I'm delighted for him to be honest, he's been massive for Munster the last couple of years and has put in performances week in, week out," Beirne said.

"He had an opportunity to go and play for his home country, why wouldn't he take it? I thought he played excellently in that first game he did get and I'm sure he'll get a few more caps with them soon and I wish him all the best.

"If he is playing in that game (against Ireland) hopefully he'll be on the losing end!"

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