As we age, our tastes change and, we can only hope, refine.

That's certainly the case with vocalist Rod Stewart, who traded in the spandex of yesteryear for dapper tux and tails, and the sexy disco growl of Do Ya Think I'm Sexy? for the deep croon of I'm in the Mood for Love.

Yes, as the performer's last two releases -- The Great American Songbook Vol. 1 and 2 -- would appear to indicate, he has indeed grown up and refined his act after 40 years in music.

"You can't be an 18-year-old rock 'n' roll star all your life," the 59-year-old Stewart says during a recent conference call with journalists from around North America.

"This was a big risk for me and I took it and it's paid off. I just hope the fans are pleased.

"You know, a lot of my fans have grown up with me so they probably like all this stuff -- when they're in a romantic moooood."

Apparently, there are enough of those fans.

Both albums of standards have sold a couple million copies each and a career that had inarguably been on the wane for the better part of a decade has now been revived.

It makes you wonder why he never tried it before, especially when he admits to having had an affection for the material for a long while now. "I don't think this is an album that I could have recorded 25 years ago," says Stewart, who brings the tour for the Grammy-nominated As Time Goes By...: The Great American Songbook, Vol. 2 to the 'Dome Monday night.

"I think I'm mature enough now to do this sort of stuff."

Helping that maturity is welcome side-effect from an experience he'd originally thought was career-ending.

In 2000, Stewart entered hospital to have a throat operation to remove a growth from his thyroid -- a lump that was initially feared cancerous but proved non malignant.

He bounced back from that scare, he thinks, with the perfect sound and pitch for crooning the old material.

"My voice is a half a step deeper than it was before the operation," he says. "I think that gave me a sweetness."

So with his pipes now primed for singing sweetly night after night, the only question that remains is, can Rod's bod stand up to all of the onstage pelvic wiggling and rock posing he's forever been known for?

"I'm probably not quite as flexible as I used to be, but I think I'm still as fit as I used to be -- I still play a hell of a lot of soccer and that keeps me pretty fit," he says, noting that there isn't much call for calisthenics while singing the standards.

"The American Songbook stuff, obviously I'm not going to throw the microphone stand about but in the first half I'll go as mad as this old frame will let me ..."

As Stewart alludes, the current show will be split into two parts, which will let those who haven't matured along with him get their fix of Maggie May and Handbags and Gladrags before an equal dose of It Had to Be You and Bewitched, Bothered and Bewildered.

And further good news for those who refuse to grow up, Stewart admits that among his upcoming recording project is something that should please recall the days of that 18-year-old Rod.

"I'm working on an album with Ronnie Wood, it's called You Strum and I'll Sing," he says. "Providing the Stones don't go on another tour next year and when I'm finished this tour this year, I think we're trying to get together to finish it off with the help of the Stereophonics."