The 38-year-old actress is said to be “doing great” after giving birth at the weekend.
“Kate had ‘Baby Boy Winslet’ on Saturday at an NHS hospital,” a representative for the actress told MailOnline.
The newborn whose name is yet to be revealed is Kate’s third child, but her husband Ned Rocknroll’s first.
The new mum’s spokesperson added that Kate’s 35-year-old husband was “thrilled to bits”.
The arrival is baby brother to Mia, 13, and Joe, nine, from Kate’s first two marriages.
The British beauty announced in June that she and husband Ned, who she wed in secret last December after meeting on holiday in 2011, were “delighted” to be expecting a baby.
In an interview in October, the expectant mother said she was looking forward to welcoming her third child and that her children were a top priority.
“I want to be as healthy as I can be, and I want to have as much fun as I can have,” she told Time Out.
“Don’t get me wrong. I like staying fit and healthy. It’s all part of a healthy attitude to life.”
