The 37-year-old has launched her own site to give women advice on topics such as fashion and relationships - and she is also using her own experiences to help her fans get in shape.
She wrote: 'So let's really do this thing!'
'I know it can be intimidating, and it may be easier to just say, 'Eh, maybe tomorrow'. Trust me, I get it. I know what it's like to juggle a lot of things: family, friends, work. We are all busy and sometimes exercise gets left behind. At the same time, I'm 37 years old and I definitely want to be fit and healthy. I want to look and feel good, and I'm betting all of you do, too.'