Yolanda Hadid Says God Gave Justin Bieber Lyme Disease for Higher Purpose (Exclusive)

Yolanda Hadid welcomed Justin Bieber into the fold as a high-profile advocate for fighting Lyme disease.

The former "Real Housewives of Beverly Hills" star praised the 25-year-old pop star for revealing he suffers from the illness earlier this month and disclosed why she believes their diagnosis is for the greater good.

"I'm just so proud of him that he understands that God has given it to us for a higher purpose and that is to help others and to be part of finding a cure that is affordable for everybody," the 56-year-old said in Los Angeles this week.

"I think he's an extraordinary young man. And I'm just so proud of him for speaking up about this very serious cause where he's gonna help hundreds and thousands of young kids that have mental symptoms that, ya know, they're not mentally ill, they have neurological Lyme disease," she added.

Yolanda has been talking about her diagnosis for seven years -- including writing a book on the subject -- and discussed how the disease is often misunderstood.

"It's an infection of the brain. When I was on 'Housewives,' I mean, the girls said, you know, on national TV, they said I had Munchausen disease. You know, they said, 'Oh she's making this up, cause how can you look that good and have that many issues,'" she explained.

"It displays in depression and anxiety and, you know, mood swings, just in all kinds of mental things. And a lot of kids get put in mental hospitals because they are not diagnosed properly with neurological Lyme disease."

The Dutch-American model divulged how the initial symptoms -- "being chronically tired, flu symptoms, joint pains, headaches, severe migraines" -- can evolve into something worse.

"That eventually turns into depression and you think you're mentally ill, like you think you're going crazy. But if you get it treated properly, that all goes away, because we're not mentally crazy, we're just sick."

Yolanda said she hopes her experience with the disease will come in handy for the "Sorry" singer.

"I've been trying to help him, you know, and send him things that worked for me and I'm just praying for him and I know he's going to pull through," she admitted. "And, like I said, I'm just so happy he understands that God has given it to people like him and me and many others and we are supposed to speak up about it, because I've helped many celebrities that don't talk about it and I'm just glad that he does."

Earlier this month, Justin took to Instagram to let his fans know about his Lyme disease diagnosis and that he also suffered "a serious case of chronic mono which affected my, skin, brain function, energy, and overall health."

He said he will reveal more details in his upcoming YouTube docu-series.