The 32-year-old TV personality has two kids -- son Harry and a daughter Belle -- with husband Dan Baldwin, reported Daily express.
"I would like to have another one. If I'm lucky enough, but I don't know when. I'll just have to wait and see. I've always thought three would be nice but you never know what's going to happen, do you?," she said.
Willoughby was left in tears when her son started going to school.
"I was fine about it until the actual first day. I think that comes with being quite busy: you sort of put things on hold and deal with them when you need to. And then on the day, I really shocked myself at how emotional I was," Willoughby said.