Singer Christina Aguilera refused to comment on her rumored pregnancy for months but now the proud mom-to-be has posed in sexy-baby-bump mode for the January 2008 cover of Marie Claire.

The “Back to Basics” singer kept mum on her pregnancy, despite a burgeoning bump and growing speculation. The January 2008 issue of Marie Claire bares all though, as Aguilera shows off her belly and confesses how becoming pregnant was a surprise.

Aguilera and music producer Jordan Bratman celebrated their two-year anniversary earlier this month. The singer told Marie Claire they were not expecting to expand their family quite so soon.

“We were planning on starting to try after the tour,” she is quoted by celebrity gossip blogger Perez Hilton as saying. “And so, I had gone off the Pill to prepare my body, because I didn’t know how much time it would take.

“You’ve heard it takes some time - except with Power Egg and Super Sperm here…I’m like, ‘Oh, my God, can you believe it just happened?’”

Aguilera went on to say how she panicked when she discovered she was pregnant – and had one more month of touring of her eight-month “Back to Basics” tour. She wore a heart monitor during performances, to protect her baby, and shared the news with her band and dancers so they would take extra care as well.

“I was paranoid. There are so many things that could go wrong - somebody could slip, somebody could fall, I could fall. There was no way in hell I was going to jeopardize my baby for my show,” the singer said.

The revealing photos she granted Marie Claire now give Christina Aguilera a place in the pantheon of pregnant belly-baring celebrities.

Among the latest are Britney Spears’ brunette and bejeweled appearance on the cover of Harper's Bazaar for the August 2006 issue, while pregnant with her second son, Jayden James.

Then there was Czech supermodel Eva Herzigova, who showed a rotund baby-bearing belly for the Italian version of Vanity Fair, earlier this year. She welcomed her first son with her Italian boyfriend in June.

“The View” host Elizabeth Hasselback took a slightly different route, posing with a protruding but well covered belly on the cover of Pregnancy magazine, for its November 2007 issue. She gave birth to her second child, a boy, earlier this month.

Of course, one has to honor Demi Moore for paving the way for all the other pregnant Covergirls, when she posed quite nude and pregnant on the cover of Vanity Fair magazine in 1991. The portrait was taken by famed photographer Annie Liebowitz and remains a classic. Moore was seven months pregnant with her and actor Bruce Willis' daughter Scout in the photograph.