Johns was invited to Australia's camp this week in Melbourne ahead of Saturday's Bledisloe Cup clash with New Zealand to help with the team with their tactical kicking.
And while it has been an exciting experience for Johns, the former Kangaroos captain is not expecting to be invited to France later this year.
"I'm flattered they would even want me to come on board with them," Johns told the Herald Sun.
"But it's all a bit hypothetical as far as I'm concerned at the moment."
Wallabies head coach John Connolly is also not willing to say whether Johns would remain with the squad until the World Cup.
"We haven't decided yet. We haven't gone that far down the track with him," Connolly said.
"We don't know what will happen. We might have a chat in the next week or so but there's been nothing to suggest one way or the other."
Meanwhile, Lote Tuqiri, who played alongside Johns in the Australian rugby league side, welcomed the suggestion of his former team-mate helping the Wallabies out in France.
"I'm not bagging us, but to win a World Cup you need all the help you can get, and (having Johns) would be a big bonus," the winger said in The Australian.
"If there are little things we can pick up here and there, it would be a good idea to get him over there.
"You just can't discount a bloke of that talent. He obviously hasn't played rugby (union) but the things he can pick up - you know he's a class above."