The 32-year-old gave birth to her first child on Wednesday afternoon (August 28).
The actress's rep said that both mother and baby are in good health.
Sigler and fiancé baseball player Cutter Dykstra announced the pregnancy in February.
The newborn's name remains unknown, although Sigler has previously stated that her baby will have a normal name.
Sigler later joked about the effects the pregnancy was having on her body, stating that her breasts had tripled in size.
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