Having become an institution in an Irish shirt since 2003, O’Connell has suddenly found his starting berth questioned by some critics.

But O’Callaghan has backed his long-time Munster teammate to respond in style against Scotland.

He said: “I wouldn't even question any of Paul's calls. I'd say if you went up to the video analysis room now, he'd be looking at Wales' line-outs from 1922 or something like that.

“The lineout is turning into an art form. It's coming down to a thing you really need to study.

“We're lucky with the lineout leaders we have. You need a few chiefs and Indians.

“I'm an Indian when it comes to O'Connell. He gives me my role and I perform it or else I get my head knocked off.