The last time Carrie Underwood set foot in Pittsburgh was the fall of 2005, when she took the stage at Mellon Arena with the likes of Anthony Fedorov and Anwar Robinson, names that only diehard “American Idol” fans will now remember.

The discussion at the time was all about whether or not Underwood was ready for stardom and whether Nashville would embrace a pretty young blonde from a TV talent contest.

We have our answers to those questions.

Since that engagement, Underwood has sold more than 7 million copies of her debut album “Some Hearts,” the best-selling debut ever for a female country artist. It won her two Grammys in 2007, including best new artist, plus Song of the Year for “Jesus, Take the Wheel.” Two weeks ago, Underwood added two more Grammys to the mantel for the revenge song “Before He Cheats.” Within country circles, the All-American Girl from Checotah, Okla., has been graced with two CMAs and an ACM.

In October, she dropped “Carnival Ride,” an even better second album that debuted at No. 1 and has sold more than 2 million copies. Pushing the sales is the fact that she seems to be everywhere — singing at football games, playing “Saturday Night Live” and looking like a rocker on the Grammys and on New Year’s Eve in Times Square.

The awards and sales are accompanied with the kind of reviews usually reserved for one of her idols, Martina McBride. The New York Times said “Carnival Ride” was “a straight-up Carrie Underwood album, and a very good one, with a handful of romps and laments that exist mainly to set the stage for the big-voiced, ’80s-influenced, Southern-accented power ballads she sings so well.”

And then there was her set at the Jamboree in the Hills in the summer of 2006. Underwood’s was putting the crowd to sleep with the ballads before turning it around with a pair of Guns N’ Roses covers.

Looks like she bridged the credibility gap.

“Yay,” she says in recent phone interview. “It’s always a little bit of a concern. I’m sure everyone goes through that. Coming off of ‘American Idol,’ I had to deal with that for a while. But, usually, the people who stay true to themselves don’t have to worry.”

While “Some Hearts” was one of those typical post-”American Idol” rush jobs, making the second record was a more relaxed and reasonable process.

“I definitely had a lot more time to look for songs and discuss directions than on the first album. It was a lot less stressful this way.”

Underwood sounds a lot more sure of herself on “Carnival Ride,” a record that features a little rock and a lot of twang. It mixes honky tonk with stirring ballads, electric guitars with fiddles and banjos, showing off her vocal range at the right times.

Underwood even got writing credits on four of the songs, the product of brainstorming with the pros in Nashville writing retreats.

“We all got in a room together, and started playing and singing,” she says. “We all start humming and talking through different experiences. There are always different ways to say certain things. Everyone was coming from a personal place.”

Except, of course, on a song like “Last Name.” “That’s definitely talking about a character,” she says laughing. “No one had gotten married to someone the same night they met them in a bar.”

Underwood arrived at the name “Carnival Ride” as it described what she calls the “wonderful craziness I’ve been through over the past couple years.”

The whirlwind success Underwood is enjoying has hardly been a guarantee for “American Idol” stars. Kelly Clarkson and Daughtry are both thriving at the moment, but Underwood’s runner-up from 2005, Bo Bice, has struggled to win an audience and the final two from 2006, Taylor Hicks and Katharine McPhee, have both been dropped from their labels.

“I think all of that hangs on a lot of different factors,” Underwood says. “A lot of times people might vote for what they like, but that doesn’t mean they’re going to go out and buy the record.”

One of the advantages Underwood has is that she has been acclaimed for more than just her singing. She made People magazine’s 2007 list of the “Most Beautiful People” and followed that with “Sexiest Female Musician,” according to Victoria’s Secret. Underwood, who keeps her personal life under wraps but has been linked to “Gossip Girl” actor Chace Crawford, doesn’t take a lot of pride in those honors, at least outwardly.

“Those are odd,” she says, ” ’cause I wouldn’t describe myself as … I don’t know if I wanted to be considered sexy. It’s flattering if people think I’m pleasing to look at, but I don’t think of myself as sexy.”

Well, let’s just say the guys who are “dragged” to the show by their wives or girlfriends will be trying hard not to stare.