Yolanda Hadid found it ''hard'' to relive some of her worst moments while writing her new memoir.

The 'Real Housewives Of Beverly Hills' star has discussed her struggle with Lyme disease and the collapse of her marriage to David Foster in her memoir 'Believe Me: My Battle With The Invisible Disability Of Lyme Disease' - and Yolanda confessed she found writing the book to be an emotional experience.

She said: ''It was hard because I struggled with a brain function issue for so many years.

''I think that I had to get some of my brain back to getting to the point of being able to write a book.''

Yolanda, 53, was diagnosed with Lyme Disease - which can lead to a number of health problems, including joint pain and even heart palpitations - back in 2012.

In her book, Yolanda is candid about how the disease has altered her life, and she's admitted it was a stressful experience putting her thoughts down on paper.

She told ET Canada: ''It was hard to relive it but also brought up all the important memories that I needed and wanted to share.''

As well as dealing with her health concerns, Yolanda's divorce from Canadian musician David Foster was confirmed earlier this year.

But the former model has insisted she would never have spoken badly about David in her memoir.

She explained: ''I was with David for nine years. I come from a place of love.''

Meanwhile, Yolanda is set to host a new reality TV show called 'Making A Model', which follows mothers and daughters as they attempt to break in to the fashion world.

Of her new venture, Yolanda - whose daughters Gigi, 22, and Bella, 20, are both world-famous models - said: ''It's called 'Making A Model' and it's about a journey of mothers and [their] daughters that want to become a model.

''We really deal with the mother and daughter relationship but also with the daughters experiencing things in the fashion industry.''