Winslet welcomed a boy on Saturday, Dec. 7, at an NHS hospital in Sussex County, U.K.
The news was confirmed by her spokesman who didn’t disclose the child’s name.
“Mother and baby are doing great,” the rep told People.
This little boy is Kate’s first child with her third husband, Ned Rocknroll, whose real name is Ned Abel Smith, Richard Branson’s nephew.
At 38, the actress is also a mother to Mia, 13, and Joe, 10, from her two previous marriages.