From PEOPLE Magazine Click to enlarge
At just a month old, Max Bratman is fussing, and his parents—pop diva Christina Aguilera and her husband, Jordan Bratman—are playing a guessing game familiar to every mom and dad: Tired? Hungry? Gassy? The two keep their cool as they try a trusted bag of tricks for soothing their son. First it's his favorite blue blanket. No luck. Then the baby swing that's "worth every penny," says the proud papa. Not this time. Finally Aguilera picks up her son, cups his small head and sings a soft melody. The little boy instantly quiets down, his squirmy body relaxes, and his tiny fingers reach up to his mom's cheek. "I'm head over heels in love," says the singer, her signature shock-red lipstick traded in for soft pink. "He's completely changed my life."

For a pop superstar with a supersexy image—this is a woman who got "Dirrty" in a provocative '02 music video—life has suddenly gotten very domestic. Although she's won five Grammys and sold 37 million records, Aguilera is relishing a deluxe maternity leave, spending quality time serenading an audience of one. "When he's breast-feeding, I just sit there and stare at him," says the singer, 27, whose version of mommy mode (flawless makeup and a comfy, chic ensemble of a striped sweater, black leggings and silver slippers) is Hollywood glam. "I'm in awe of this little miracle." Adds Bratman, 30, a Bronx-born music exec who married Aguilera in a $2 million wedding in Napa Valley in 2005: "It's brought us even closer together. He's a product of our love."

Luckily, little Max Liron Bratman (combined, his Latin first name and Hebrew middle name roughly translate to "our greatest song") is so far a "sweet, mellow baby" who inherited his dad's brown hair and his mom's ability to turn heads. "He's a good combination of both of us," says Aguilera. "He smiles a lot already, and he has the same little Elvis side smile that I do." What about her lung capacity? "He's not a big crier, so he hasn't really belted it out yet!" He's also no stranger to show business—Aguilera was about to start the last three-month leg of her world tour for her Back to Basics album when she learned she was pregnant. "I couldn't figure out why I was late," she says with a laugh. "I really doubted I was pregnant. But I took a test and it was positive, and then I took another test and it was positive. My jaw dropped and I started tearing up." Says Bratman, who was in New York at the time: "When I got home there was a whole line of [pregnancy] tests!"

She completed the tour in Asia and Australia with Bratman at her side, wearing a heart monitor onstage while hanging from a circus pinwheel and riding a carousel horse. The first sonogram prompted Max's pre-birth nickname. "He was just a little circle, and the doctor said it was the yolk sac," says Aguilera. After that, "his nickname throughout the pregnancy was Yolky and I was Mama Yolky. Now he's the Baby Formerly Known as Yolky." During her pregnancy, Aguilera had no morning sickness but developed "a craving for sweets like never before," she says. "SweeTarts, lollipops, anything with sugar I loved." And when the time came to find out the sex of her baby, it was a no-brainer for Aguilera, a self-described "super-planner" who documented her pregnancy in scrapbooks filled with photos (including one of all those pregnancy tests), sonograms and notes in her intricate handwriting. "I had to know what colors to buy!" she says. "I need to be prepared at all times."

Including for the birth itself. "I didn't want any surprises," she says matter-of-factly of her decision to deliver via scheduled C-section at week 37 of her pregnancy. "Honestly, I didn't want any [vaginal] tearing. I had heard horror stories of women going in and having to have an emergency C-section [anyway]. The hardest part was deciding on his birthday. I wanted to leave it up to fate, but at the same time I was ready to be done early!"

When the big moment finally arrived, "the instant I heard his cry, the waterworks started," says Aguilera. Bratman, who filmed the birth and played the music of Miles Davis throughout, says, "We've played the [birth] video several times since, and all you can hear is me going, 'Oh my God!' I was beaming the entire time." And when they placed Max in Aguilera's arms, "I said, 'Hi, Papa, hi, my little angel," she recalls, "and he looked up at me and opened his eyes for the first time. The connection was incredible. You can't believe the love you feel."

That night the three cuddled together for the first time as a family in Aguilera's hospital bed. "It was magical," says Aguilera, who started breast-feeding that night. "It's amazing: Your body is this supplier of food! I'm in awe of it."

Nurturing her family is especially sweet for Aguilera, who has talked openly about her own difficult childhood. The daughter of Fausto Aguilera, 58, an Ecuadoran-born U.S. Army sergeant from whom she is now estranged, and his Irish-American wife, Shelly, 47, Aguilera was just 6 when her parents divorced. "My family was always struggling with money," says the singer. "It's surreal to be able to give my child this lifestyle."

That lifestyle includes a round-the-clock baby nurse and a brand-new nursery in her sprawling Mediterranean-style mansion, which was made famous by the previous residents, Ozzy Osbourne and his family, who lived there while starring in their MTV reality show (see box). Aguilera also plans to resume work this month, recording a new album in her home studio. Working out is another priority: After she gets the okay from her doctor (around the six-week mark), she will return to the gym with a mix of weights, boxing and treadmill. Already, "my body is going back to its normal shape, and I'm like, 'Did [the pregnancy] ever happen?'" she says. "I've never had more respect for the female body."

Before long the new mom plans to bring her littlest fan on tour. "He'll be a world traveler at an early age," she says. In the meantime, Max is getting an earful of his parents' musical tastes. "Yesterday we had Led Zeppelin blaring through the house," she says. "Most new moms play Beethoven, but we're playing Metallica, Bob Marley, the Stones." And Max is already keeping musicians' hours too: "Just like his mom," says Aguilera, "he's a total night owl."

Looking ahead, she admits she'd love more kids. "Not yet!" she adds. "But I always wanted a big family." And before she knows it, there will be first words, first steps—and maybe even first dance moves. "I can't wait to see him wiggle his little bootie and stomp his feet for the first time," she says. "As exciting as it's been so far, it's still only the beginning!"