The girls, Eden and Savannah, who were born at a Los Angeles hospital, are the first children for the Desperate Housewives actress, 44, and her stockbroker husband Tom Mahoney, 49, who married in June 2006.
"Mother and babies are all doing well," says Cross's rep, Heidi Slan.
Cross had been on bed rest since January, but producers of her ABC hit brought production to her home for some scenes.
Set designers painted Cross's bedroom the same color as her character Bree Van De Kamp's boudoir, and moved in furniture from the set. At the time, show creator Marc Cherry told PEOPLE that Cross was "bored out of her mind (in bed), so she said, 'Bring the camera here – I want to act.' "
Her rep told the Associated Press that the bed rest was merely a "precautionary measure," and Cross herself said in December that she'd been having a problem-free pregnancy.
Lisa O'Connor / ZUMA
Still, she told PEOPLE in December that having babies later in life is "like a miracle ... I didn't think it would happen."