Music: How guitarist Orianthi wowed musical giants, including Michael Jackson

The three pop-rocking talents sharing the Tower stage next Thursday night on the glitzy "Glam Nation" tour have a thing in common. All have come oh-so-close to winning a crown. All were arguably "robbed."

Well-known are the sagas of Adam Lambert and Allison Iraheta, both major-league belters and distinctive stage personalities who arguably could have (should have) taken a victory lap on "American Idol."

But equally talented and deserving is a 25-year-old Australian singer/guitarist who answers to the name Orianthi. Her big chance at stardom was quashed in June 2009 by a tragic death in her creative family.

Orianthi (Panagaris) was the boisterous, blond-haired talent Michael Jackson had entrusted to keep him rocking and fresh, to play all the flashy guitar lines (and even come up with some new ones) for his comeback show, planned to land last summer at London's O2 arena.

After those 50 sold-out dates, the extravaganza probably would have toured worldwide, restoring Jackson's luster and leaving millions agog over Orianthi, I'm thinking.

"You've seen the ['This Is It'] documentary, right?" the talent asked in her distinctly Aussie accent during our recent chat from the tour bus. "Even there, you can tell. It would have been the best concert ever."

Jackson, whom Orianthi characterizes as "a very sweet person" and "totally cool," was not the first major musician smitten by the girl.

As a young teen in the southern Australian town of Adelaide, the guitar-aholic had wowed fusion phenom Steve Vai to the point that he let her open a show for him.

A couple years later, Carlos Santana was in town for a concert, was given a tape and invited Orianthi up on stage to jam for the hometown crowd.

Santana then connected her to Paul Smith, maker of PRS Guitars, who invited Orianthi to gig at a big-music instruments convention in California. A scout from Geffen Records heard her there, which led to the artist's signing, her three-years-in-the-making debut album ("Believe") and a spotlight appearance on the 2009 Grammys backing Carrie Underwood.

And that's where Michael Jackson's people first spotted her.

"His musical director saw me, then checked me out on MySpace and left a message asking me to come in and audition," she recalled. "At first I didn't believe it was real. I played the 'Beat It' solo, and afterward Michael came up and gave me a big hug and told me I had the gig."

Orianthi just about bursts through the screen in the "This Is It" documentary, confidently strutting the rehearsal stage alongside Michael, shredding florid lines like a seasoned pro, even earning an extralong solo - "your moment to shine," Michael told her - during "Black or White."

"There was always film or videotape rolling during the rehearsals, and we ran the complete show a bunch of times," she said. "They were recording mostly so Michael could study and work on things - he was quite the perfectionist. And the thinking was, a documentary would come out of it that would be the bonus for a videodisc of the complete London concert. It's something the way they patched together performances of songs from different rehearsals. And watching it still shocks me, that he's no longer here."

Her own album was originally released last November, then updated a couple months ago as "Believe (II)" with four new tunes, including her snappy single, "Shut Up and Kiss Me," and a great cover of John Waite's "Missing You."

The set casts her as a tough-nosed pop-rock vocalist in the Avril Lavigne vein, with the added allure of being able to toss off some cracklin', though all-too-brief guitar solos.

"That's why I want people to see the live show. It's more riff-based, the guitar solos are longer," she shared. "And that's the way the next record will be - a lot more rocking, with elements of blues and country, but still super commercial."

PRS Guitars recently issued an Orianthi signature edition instrument of which she's extremely proud. The musician is clearly hoping to inspire other young females to pick up an ax and wail.

"Growing up, I didn't have a lot of role models - Bonnie Raitt, Lita Ford, Jennifer Batten. And I had a lot of trouble being taken seriously, took a lot of grief at school. Girls are supposed to sing. It's the guys' thing to play the guitar. Crossing the line is kind of like trying to be a male ballerina. But if you work long and hard enough, are really passionate about it, people will finally shut up and listen."

Tower Theater, 69th and Ludlow streets, 8 p.m. Thursday, $37.50, 800-745-3000, www.livenation.com.