Caitlyn Jenner had secret breast reduction surgery over 20 years ago.
The 66-year-old reality TV star - who revealed she was transgender last year - admitted that she first grew breasts through hormone treatment around 1990 but decided to have them removed after meeting and falling in love with her now ex-wife Kris Jenner.
She said: "I started on hormones. I was a good 36B. I loved them. I thought this was fabulous. My mission at that point was to transition before I was 40. Got to 39 ... I just couldn't go any further.
"[Kris and I] hit it off from day one. I was very honest with her. I had to be, I was a 36B. I actually had my boobs removed. I never told anyone that."
While Caitlyn had originally wanted to transition by the age of 40, she changed her mind and decided to focus on her relationship with Kris.
Speaking in an interview taped at the 2016 MAKERS Conference and aired on 'Today', she explained: "Everything [with the transition was] really heading the right direction, and I made this decision to kind of move on [with] my life and Kris and I together and this family. 'Okay, I've got to get rid of these gender things and get off hormones and this and that.'"
Caitlyn - who was previously known as Bruce Jenner - also claimed that Kris knew she liked to wear women's clothing but just asked her not to do so at home.
She said: "The rules with Kris and I were, "Don't dress up, certainly around the house. If you really need to do that, when you're on the road, take stuff and do that. So I did that for years."