The Real Housewives of Beverly Hills star tells PEOPLE Now that news of the Fosters' separation "knocked me sideways"


It’s been a challenging year for Yolanda Foster, but her Real Housewives of Beverly Hills costar Lisa Vanderpump is sure next year can only get better.

Although the rest of the Beverly Hills crew hasn’t seen Foster much because filming is finished, the Vanderpump Rules star says she has reached out a couple times to offer her support to Foster, who turned 52 on Monday and is moving forward with her split from husband of four years, David Foster.

“It was her birthday yesterday, and [I] just said, ‘It’s going to be a great year ahead. Have faith, and hopefully it will be,” Vanderpump, 55, tells PEOPLE Now.

As previously reported by PEOPLE, Foster officially filed divorce papers, citing “irreconcilable differences, on Tuesday. The couple announced their separation after nine years together in December.

“I don’t think any of us expected it whatsoever,” she says. “The fact that it was announced on the night of our premiere knocked me sideways.”

Vanderpump says the split hasn’t affected her relationship with Yolanda. Right now, Vanderpump is focused on being there for her costar, who is also battling Lyme disease.

“I’ve been married a long time, [and] it must be very difficult,” she says. “I want to be supportive.”

The Real Housewives of Beverly Hills airs Tuesdays (9 p.m. ET) on Bravo.