Yolanda Hadid's daughter, 20-year-old Bella Hadid, is super proud of her mom for releasing her new book, Believe Me: My Battle with the Invisible Disability of Lyme Disease.

While attending the former Real Housewives of Beverly Hills star's book signing earlier this month in Tribeca, Bella spoke of the new publication, which chronicles her mother's battle with Lyme disease as well as her marital struggles and family life. 

“I’m so incredibly proud of my mom always, but especially with this book. I was so excited to be here and support her!” Bella told Us Weekly magazine during the signing.

Hadid's two youngest children, Bella and Anwar, also suffer from Lyme disease but her oldest child, daughter Gigi, does not.

“I just was hopeless and didn’t see how I was going to get out of the dark hole,” Yolanda told the magazine of her health crisis on September 12. “I wanted to die, but the next second, I looked at a picture of my sweet kids. They are my reason for fighting... My greatest gift would be if I can find the cure before I leave this planet, so they can live a life they deserve.”

Yolanda learned she was suffering from Lyme disease just months after tying the knot with David Foster, whom she's since divorced.

”I just had to surrender, like the first year, I fought it every day and I would be miserable about being miserable," she recalled. "At some point you just learn to surrender to your path. This obviously was my path for five years and the healing clock is, you know, the universe's time and not on my time."

To hear more about Yolanda Hadid, her family, and her health struggles, pick up a copy of Believe Me: My Battle with the Invisible Disability of Lyme Disease and check out her September 2017 interview with Access Hollywood below.