Yolanda Foster's divorce announcement caught her fans and close friends by surprise. Less than one week ago the star of Bravo's "The Real Housewives of Beverly Hills" announced that she and husband David Foster would be going their separate ways. Now, co-star Lisa Vanderpump is speaking out about the divorce, saying she was completely blown away by it.

According to a report from Us Weekly, the "RHOBH" star was at a TrevorLIVE Los Angeles event on Sunday when she was asked about Yolanda, 51, and David, 66. Lisa told the publication she had seen her friend and cast mate recently and had reached out to her about her divorce. While Lisa remained tight-lipped on how the former supermodel was doing in the wake of her separation, she told Us she was "very sad" for Yolanda. She shared she never expected Yolanda and her husband to split, adding that their marriage seemed so "unbelievable."

"I saw her last night. I have reached out to her before, and I, I just feel very sad about that. 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," she said. "I didn't see it coming, and I hate that."

Lisa isn't the only "RHOBH" cast member -- past and present -- who was shocked to learn that Yolanda and David had decided to divorce. On Dec. 2, Kyle Richards appeared on Bravo's "Watch What Happens Live" where host Andy Cohen asked her about the news. Much like Lisa, Kylie, 46, claimed she had no idea the couple was struggling. She said that perhaps their issues were magnified by Yolanda's battle with Lyme disease. Adrienne Maloof, who left "RHOBH" a few seasons ago, and Eileen Davidson sent their condolences to Yolanda and David on Twitter.

Yolanda and David broke the news of the divorce via E! News. The couple released a joint statement in which they revealed that they had "decided to go our separate ways." They claimed they had many happy years together, which they were "grateful" for, and said they had tried as hard as they could to keep their marriage together. The couple ended their message on a hopeful note, saying they planned to try and maintain the same level of "love and respect" they currently have for one another throughout the divorce proceedings.