Lisa Vanderpump, star of Bravo's hit reality TV show "The Real Housewives of Beverly Hills," opened up about her reaction to her co-star Yolanda Foster's divorce, Us Weekly reported. During a TrevorLIVE event on Sunday in Los Angeles, Vanderpump expressed sadness for Foster's loss of marriage.

"I just feel very sad about that," the 55-year-old British reality star and restaurateur told Us Weekly. "So I just feel very sad about that because I didn't expect it, and I always thought she always had this unbelievable marriage, so I'm sad about that. Very sad about it."

Foster announced her split from her husband David last week, as previously reported by HNGN. The couple spent nine years together, of which they were married for four. She credited the everyday stress of life, work, health and raising children as the reason why the couple grew apart. Her 2012 Lyme disease diagnosis especially took a toll on her relationship with David.

Vanderpump, who is married to former British soccer player Ken Todd, expressed remorse to see the demise of what seemed to be a happy marriage. But while Vanderpump seemed supportive of Foster during her divorce, she didn't seem very supportive of her co-star in the season six premiere of "RHOBH," where she questioned whether Foster's health issues really are due to Lyme disease.

Foster addressed Vanderpump's comments in her Bravo blog post, which was posted shortly after the episode aired.

"I am blessed to have a voice and a platform that can bring awareness to not only my disease but to the most profound lesson of it all," Foster wrote in her Bravo blog, "which is to lead a life with compassion, kindness, and without judgement, for everyone you meet is fighting a battle you know nothing about."