"The Real Housewives of Beverly Hills" is about to return this week, and ahead of the Bravo show's sixth season premiere, Eileen Davidson is speaking out to defend Yolanda Foster, saying that the former model's Lyme disease battle is very real.

"I know for a fact that she is not faking it," Eileen said to OK! Magazine (via Radar Online) about Yolanda's condition.

Yolanda was diagnosed with the debilitating disease in 2012, and since then, she has raised awareness of the disease in hopes of finding a cure for it. The star has chronicled her ongoing battle with Lyme disease on Instagram, often posting pictures of the various treatments that she has tried. Recently, she also revealed that two of her children, Bella and Anwar, are also battling the disease.

"It's really not easy," adds Eileen. "I care very deeply about her, and I see her struggling…It's hard to see your friend go through this thing, especially in front of cameras."

In the season 6 promo for the show, Yolanda is seen trying various treatments as she says that she is willing to try anything to find a cure. She also told Eileen and Lisa Rinna that she doesn't remember what it's like to be normal.

Earlier this year, there were reports that some of the ladies of "RHOBH" have questioned Yolanda's condition. According to Radar Online, Yolanda got into a huge fight with some of the ladies at Kyle Richards' recent party.

"The ladies seemed to think that Yolanda has become a hypochondriac, or was making herself sick from undergoing so many alternative treatments," said a source to the website, adding that the mother of three got very upset and "did indeed yell at them."

While Eileen admits that she has never gone with Yolanda to one of her treatments, the soap opera star says that she has "supported her in many different ways" and considers her to be a friend.

"The Real Housewives of Beverly Hills" season 6 premieres Dec. 1 at 9 p.m on Bravo.