When it comes to out-of-the-blue selections, Sam Carter’s call-up to make his Wallabies debut is right up there.

Not only did the unheralded 24-year-old beat heavily tipped Waratahs lock Will Skelton for coach Ewen McKenzie’s favour, Carter ousted 48-cap veteran James Horwill to earn a starting spot against France in Brisbane on Saturday.

The elevation has been so rapid, even Carter couldn’t quite believe it when he was told on Monday afternoon he’d be making his first Test appearance.

“I was told just before the team announcement. I was focusing on the lineouts with Bladesy (set-piece coach Andrew Blades) and, as soon as I was told, I completely forgot what I was talking about,” he said.

“There’s a lot of information I have to go across between now and Saturday’s match but I’m just trying to stay on top of it and control everything.”

Carter is the son of former Wallaby David Carter, who earned a reputation as an uncompromising back-rower during the late 1980s.

McKenzie said Carter’s workrate and defensive qualities would be crucial in an anticipated tough forward battle against the French.

“He’s a very natural footballer,” he said.

“Anyone that saw him play on the weekend would appreciate all the subtle elements in attack and defence he can contribute.”

Carter admitted he’d anticipated an awkward conversation with Horwill when the former skipper approached him after the team announcement.

But instead, he’d been offered all the support he needed from the man whose spot he’d just taken.

“Kev’s a class act,” Carter told AAP.

“Anything I can learn off him is obviously a bonus heading into this Test. There was no hard feelings.”