Who knew that it would take Dolly Parton and an ascot scarf, or cravat, to finally break an Australian rocker out of his shell?

On Tuesday night’s episode of “American Idol,” hunky Michael Johns at long last delivered the star-quality performance many viewers had been expecting of him for weeks — and the boy from Down Under topped it off by wearing an ascot instead of a tie.

With country music icon Parton as the show’s guest mentor, Johns (at 29, the show’s oldest contestant) sang “It’s All Wrong But It’s All Right” — a choice that was met with rave reviews from the judges.

Randy Jackson called it a “blazing hot performance” and Simon Cowell said it was the best he had ever heard Johns sing.

Even Parton herself was impressed, saying she’d like to write songs for Johns one day.

“I’m hoping he does become a star,” she said in an interview recorded after Johns sang the song to her during a rehearsal.

Tuesday night marked the second straight week Johns received gushing praise from the judges. Previous performances by the Aussie, who has been compared to Michael Hutchence and Jim Morrison during the two Beatles weeks, left the judges unimpressed.

So is Johns, like David Cook, moving up in the “Idol” food chain?

Fans on the “Idol” message boards think so. Or maybe they just liked the scarf. As one fan wrote: “The ascot was like the icing on the cake tonight.”