Katie signed copies of her 49th (!!) book, He's The One, at Waterstones in the Freshney Place shopping centre in Grimsby on Sunday (30 June), before moving on to Doncaster.
As she has throughout her fourth pregnancy, the model she kept her baby bump largely covered with loose clothing and a scarf.
Katie recently told Reveal that she had kept more private during this pregnancy and was actually surprised no pictures of her bump had surfaced yet.
The model and author is expecting a baby with her third husband Kieran Hayler later this year. She is already mum to son Harvey from her relationship with Dwight Yorke, and son Junior and daughter Princess from her marriage to Peter Andre.
In an interview with The Independent this weekend, the 36-year-old suggested she was happier to stay away from the limelight after years of being high-profile.
"When I was married to Pete, I don't know what I was thinking," she said. "Everything we did was documented, every party, every trip, on the telly, in magazines. It's not healthy."
Katie, also known as Jordan, added that son Junior now wants to be famous, telling her he wants to do things like go on Britain's Got Talent.
"He keeps telling me he's famous, and I'm trying to tell him that just because his father puts him on his TV show, that doesn't make him famous himself."
More stars giving birth in 2013: pictures!