The new mum revealed the good news via Twitter, saying: "Beyond delighted to announce the birth of our baby boy last week. All doing well & we couldn't be happier... 3 really is the magic number!"
Cat and Patrick became first-time parents to a baby boy
The So You Think You Can Dance host, who first showed off her growing bump at the Emmy Awards in September 2015, announced the news earlier the same month. "Exciting news.... Paddy and I are so happy to be expecting our first child in the Spring..... Lucky us," the TV presenter tweeted.
Patrick, 44, confirmed the news and expressed his joy on Loose Women, telling the panellists: "Yes. There is a little baby on the way. In the spring. Very exciting, God love it. It's going to have this as a father!"
Meanwhile, Cat took to pregnancy very naturally. "I'm actually fine. I'm not too bad at all. I'm looking forward though to this week being over so I don't have to wear high heels for a long time. There's been a lots of heels this week," the 38-year-old told E! News when asked about her pregnancy cravings.
The new mum announced the good news on Twitter
"I managed to squeeze myself into this Monique Lhuillier gown. We had to let the back out a little bit but everything else is pretty okay. I'm hanging in there."
The bouncing baby boy is the first child for Cat and her comedian husband, who secretly tied the knot in Rome in 2012.
The pair secretly wed in Rome in 2012
The happy couple first met when they presented talent show Fame Academy together in 2002. The pair stepped out as a couple a decade later in March 2012 and married at St Isidore's College Church in Rome in September of the same year.
"People wait [to get married] because they need to get to know each other first," he explained. "Cat and I were friends for such a long time, a good ten years, so we already knew each other very well."