By Michelle Tan
December 24, 2007 12:00 PM

At the New York album release party for Jennifer Lopez‘s latest CD, Brave, in October, there was more than music to celebrate. When producer Swizz Beatz grabbed a seat next to the guest of honor and her husband, Marc Anthony, in the VIP room, “[Marc] grabbed my hand and put it on her stomach,” says the couple’s longtime friend, who found out that night that the singer was going to be a mom. “She was glowing so bright and looking at me with the smile of all smiles. I was just like, ‘Wow! It’s show time!'”

Not so much. Maybe the Jennifer Lopez of old would have made more of a media spectacle of her joyous baby news, but the woman formerly known as J.Lo has turned into J. Down Lo—ducking the spotlight and choosing to keep her pregnancy unconfirmed until the very end of her tour with Anthony last month. “The situation is very personal and they want to have their space,” says Swizz Beatz. “Jen wanted to be able to have a pregnancy without people going crazy.” Same goes for her family—which will be doubling in size when she gives birth to twins early next year. (She’s getting the best of both worlds: Multiple sources have confirmed to PEOPLE that the singer is expecting a boy and a girl.) The singer-actress-designer “has come to a different place in her life. Her career seemed to come first in her previous relationships,” says a source close to the couple. “Now she is working towards a more rewarding and lasting legacy: her family.”

For Lopez, 38, her shift from the fast lane to the carpool lane is a welcome change. No longer a regular in the Miami or L.A. scenes since her 2004 marriage, Lopez is “the real suburban deal,” says designer Michael Kors, who grew up just 20 minutes away from the Long Island, N.Y., manse that she now calls home and where she is designing one of three nurseries for her babies (see box). “Jen is slowing down,” adds Swizz Beatz. “She’s just chillin’ right now.” Confirms Lopez pal rapper Fat Joe: “She’s going at her pace now.” Even Anthony, 39, has noticed a change in his wife of three years, telling a friend, “The pregnancy has made her more patient.”

It’s a trait that’s bound to come in handy with two bundles of joy on the way. “She wanted this more than anything and she got it—twice!” says director Leon Ichaso, who worked with the lovebirds on the film El Cantante. While the double diaper duty may prove daunting to some, no one doubts that Lopez will rise to the challenge. “No one works harder than Jennifer Lopez in any situation,” says a friend of the couple’s. “She will devote her life to becoming an amazing mother.”

But just in case, she’s got a second set of hands to help with those late-night feedings. “Marc has experience being a great father,” Swizz Beatz says of Anthony, who has three children—Arriana, 13, Cristian, 6 and Ryan, 4—from previous relationships. Always a team, “Jennifer and Marc are hands-on with every aspect of their lives,” says a close friend of the couple’s. While Dad might be known as the jokester in the family, “[Jennifer] will invent her own language for the kids with little noises and songs,” says Ichaso.

Lopez is already planning on launching a new fragrance, Deseo Jennifer Lopez, in February, but once her son and daughter make their grand entrances into the world, “She can’t be as much of a workaholic anymore,” says Ichaso. “Mothering will be her career and it will be a new Jennifer.”