The television presenter and husband Kris Thykier have yet to name the new arrival, their third child together. Winkleman gave birth yesterday evening, the Daily Mail reports.
Winkleman and Thykier, who married in 2000, are already parents to Jake, 8, and Matilda, 5.
"We can confirm that Claudia has had a baby boy," her spokesperson said.
When announcing the pregnancy in March, the 39-year-old thanked fans for their messages, while joking: "It's true I'm having a baby. Although to be frank, on the scan it looked more like a goat."
Winkleman recently stepped down from her hosting role on Strictly Come Dancing spinoff It Takes Two, admitting: "I can't believe it. I will miss it so much."
Yesterday, it was confirmed that Zoe Ball will take over the weekday show.
> Claudia Winkleman's C4 show cut down due to pregnancy