The reality TV star, who recently released her autobiography Surviving Guns, Gangs and Glamour, underwent the surgery to get a "natural" shape that will "look good in a dress".
"You hear of people booking in for surgery and not getting the look they wanted, and that was me before," said the 30-year-old.
"I just wanted to get the shape sorted out. My boobs were sitting quite far apart so I wanted something which gave me much more of a cleavage.
"I definitely don't want them massive like Jordan or super-pert like Victoria Beckham, just something natural which is going to look good in a dress."
Horgan-Wallace visited the The Hospital Group in Bromsgrove to boost her DD-Cup assets.