The 34-year-old is all set to marry striper Kieran Hayler at a huge seaside bash in Weston-super-Mare, reported Daily Mirror.
"Katie had planned all along to have the ceremony on Saturday but she had been trying to keep it all. Once it became public knowledge, she quickly moved everything around," a source said.
"It obviously caused a lot of work for some of the people involved, because weddings are normally planned so far in advance. Now some guests have had to quickly request time off work, too."
She has another son, Harvey, 10, with footballer Dwight Yorke. She married cage-fighter Alex Reid in 2010 but they divorced a year later.