Cat, 41, took to social media to share the news with her fans, revealing that their two-year-old son, Milo, is going to be a big brother.
She wrote: “Over the moon to share that Milo is going to be a big brother! Can’t wait to be a family of four in the spring. We’re all so excited.”
Cat has always been honest about her desire to expand her family, previously saying: “I would love some more. But I have got to get on with it if I do.
“When you go for your check-ups they call you a ‘geriatric mum’. That is the terminology they use, I swear.
“They say, ‘Ma’am, you are triple high risk’.”
Cat and Patrick, 46, tied the knot in a secret marriage in Italy back in 2012 after initially being best friends.
She previously explained: “There were no more games and it all happened very quickly because we were older and comfortable in our own skin.
“A lot of our friends knew it would happen before we did, but I honestly had no idea.
“I wouldn’t have wasted so much time! And thank God he happened to be around and that I hadn’t missed him in the process.”