The Circle Of Friends star, who gave birth to son Henry in 2008, said that although motherhood is difficult, she loves every minute of it.
Driver is quoted by Yahoo as saying: "The love, the unquantifiable love, it just takes my breath away. My son's face in the morning or if I hear him saying, 'Mama, Mama' and when I go in he's just sitting there in his crib... it feels like Christmas."
The 39-year-old actress added: "I want Henry to have brothers and sisters, or a brother or sister. It would be really nice for him."
Driver has never revealed the identity of her son's father.