The 38-year-old delivered the baby at an NHS Hospital in Sussex county Dec 7, reports people.com.
"Mother and baby are doing great," her representative said.
This is the actress's first child with husband Ned Rocknroll, whom she got married to last December. The couple announced the pregnancy in June.
Winslet already has two children - Mia, 13, and Joe, 10, from her previous relationships.
--IANS (Posted on 12-12-2013)