Hailey Bieber was able to keep her pregnancy secret for six months because she had a "small" baby bump

She told W magazine: "I was honestly able to keep it quiet because I stayed small for a long time. I didn't have a belly, really, until I was six months pregnant, which was when I announced it. I was able to wear big jackets and stuff."

Hailey went on to admit she "probably could have" kept the pregnancy a secret all the way through to the birth, but she didn't like keeping such big news quiet.

She added: "I probably could have hid it until the end. But I didn't enjoy the stress of not being able to enjoy my pregnancy outwardly. I felt like I was hiding this big secret, and it didn't feel good. I wanted the freedom to go out and live my life."

The social media star also opened up about her struggle with morning sickness during the early days of her pregnancy, admitting she suffered a lot in the beginning.

She joked: "I don't know why they call it that because it lasts all day long; we need to change the name."

Hailey revealed she has been sticking to a high protein diet of "lots of eggs, chicken, and steak" and her one big indulgence has been hiring a personal chef to prepare her dinners at home, which she admits is a "huge luxury".

Hailey added of her pregnancy cravings: "I just listen to whatever the baby wants. If the baby wants pizza one day, we're doing pizza."