The 33-year-old singer already has daughters Molly, 11, and Lilly Sue, 10, with her first husband Brian McFadden, and Heidi, six, and five-year-old son Max with her second spouse Mark Croft, reported Daily Mirror.
"We have just found out we are having a baby - I am three months pregnant. I have food and a baby in my belly, the best friends in the world, a great job and I am a very lucky girl. I am very grateful," Katona said.
The star is also preparing to walk down the aisle for the third time later this year when she weds childhood friend George after he popped the question in April at the top of Blackpool Tower, Blackpool, in Lancashire.