LAS VEGAS – Though she’s undeniably warm and gregarious, you can hear a bit of irritation creep into Celine Dion’s voice when her years away from the pop music world is referred to as “time off.”

“I don’t think it was a break,” she says politely but firmly. “I worked for five years.”

Indeed, Dion’s “A New Day” concert extravaganza on the Las Vegas strip may have been more demanding than pop life. The French-Canadian chanteuse performed several days a week in the ambitious, Franco Dragone-directed show, which was heavy on dancing, theatrics and of course Dion’s booming voice. The career of Celine Dion the Entertainer was vibrant and thriving.

But for all practical purposes, the career of Celine Dion the Pop Diva was all but dormant where it once had its biggest impact – the recording industry.

While thousands packed Caesars’ Palace to hear her sing every night, Dion – who has sold 50 million albums in the United States alone since her 1990 debut, and had one of the biggest songs in pop history with “My Heart Will Go On” – disappeared from the charts. Though she released a French-language album and a CD to accompany an Anne Geddes photo book titled “Miracles,” Dion decided not to put out a pop disc during her Las Vegas tenure. Her last proper studio album release was 2003’s double-platinum “One Heart,” released just as the show began.

So as “A New Day” winds down this year and she releases her comeback record, “Taking Chances,” on this week, Dion finds herself in many ways starting over, trying to reclaim her place after being a pop queen in exile.

“She’s more nervous than she was before. The fact that she hasn’t been in the pop arena for five years, she’s pretty nervous about it – and me too by the way,” says her husband and manager, Rene Angelil. “We don’t know if people will accept her, if the fans are still there. We know that she has fans … (but) a lot of things have changed in the music business in the last five years.”

Something else has also changed as well: Dion’s sound. The woman known (and often parodied) for her bombastic love ballads now has a harder edge to her music. Some of the songs are decidedly up-tempo and would fit in easily on a Kelly Clarkson CD, with their emphasis on heavy guitars. And on the album’s most intriguing track, “The Woman in Me,” Dion sounds like she’s singing in some nefarious dive bar. Growling her way through the blues belter, she blows away her reputation for sometimes saccharine material.

Even the album’s first single, the ballad “Taking Chances,” seems more mainstream pop than her usual adult contemporary vibe – like a calculated attempt to capture new listeners.

But Dion, 39, says she wasn’t intentionally trying to change her sound.

“I picked those (songs) without knowing that it was very different, to be honest with you,” she said via phone after taping an episode of “The Oprah Winfrey Show,” part of a high-profile media blitz planned for the week of the CD’s release.

“When I went in the studio and I sang them I just enjoyed myself so much. And now I listen to it and I notice it’s definitely edgier but this is where I am right now,” she adds. “I’m not a new Celine but it’s just that I’ve evolved and this is where I am in my life and my career right now. … the feeling that I feel. I’m definitely more mature and more grounded.”

John Shanks, who produced several songs on “Taking Chances,” including the title cut, says her new sound shows “she’s viable and that she is competitive.”

“It shows that there are many sides to her and it’s just how she’s been showcased in the past. … I don’t think she’s chasing anything at all, she’s not chasing a sound. I think it’s a very natural growth.”

But after being gone from the pop scene for so long, even a new sound may not be enough to connect with listeners. So far, the acoustic-leaning single “Taking Chances” hasn’t registered on the pop charts, although it’s at No. 11 on the adult contemporary charts.

One station that is taking a chance on “Taking Chances” is New York’s top 40 radio station Z100. Sharon Datsur, the program director, says the typical response from listeners is “shock that it’s Celine Dion, first of all, and then they say, ‘Wow, I love the song.'”

Though the first single has been slow to catch on at other radio stations, Datsur said the album, which includes production by R&B; singer-songwriter Ne-Yo, rocker Ben Moody and Linda Perry, is the smart way to reintroduce Dion and create a different identity with the audience.

“I’ve listened to the whole album and they did this really smartly. They are working with some of the top producers that have produced some of the biggest pop hits in the last five, 10 years,” she says. “For so many years, a lot of people kind of associated her with adult contemporary – an older audience.”

While Dion admits to being “more nervous” about her new album than past one, she’s also quick to assert that she’s not obsessed with trying to recapture the multi-platinum status of her glory years. Part of the reason for that is also the reason she planted herself in Las Vegas for five years: her 6-year-old son, Rene-Charles.

“I do worry, but for the important things,” she says forcefully before a recent performance at Caesars Palace. “My priorities changed since I became a mommy. I love to sing, I love to perform – (but) it is not my life.”

To that end, Dion and Angelil are already looking past the next year, during which she plans a major world tour, and planning to add to their family. “This is our big project,” Angelil says.

In fact, Dion, who is quick to point out that she has been working pretty much straight for the past 25 years, is looking forward to her next hiatus from the pop arena – when she will truly have a real break.

“I miss to be home, we’re building a house right now,” she says wistfully. “I’m about to meet my life soon, you know, so that’s what I miss the most.”