Heigl & Ramirez Learn News About 'Grey's' Co-Star Justin Chambers

Utter shock was the look on Katherine Heigl's face Thursday, as she found out from the paparazzi that her friend and "Grey's Anatomy" co-star, Justin Chambers, checked into the same UCLA Medical Center psych ward as Britney Spears.

"When?" she asked the photogs. "I just talked to him last week, he was fine," she said as she was leaving Il Picolino restaurant in Beverly Hills with her mom.

[ Katherine Heigl Hears About Justin Chambers' Hospitalization - Watch the Video ]

After learning the news, Katherine sat with her mother, making intense phone calls for about half an hour as she paced back and forth, before battling her way back to her car.

Fellow "Grey's" actress Sara Ramirez had a more subdued reaction in New York City Friday morning.

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Access caught up with Ramirez at a show kicking off New York Fashion Week. Sara had not heard the news about Justin either, but said she, "hopes he is feeling better."

The reason for Justin's hospital stay — According to his rep, the father of five suffers from a sleep disorder and voluntarily checked himself into UCLA Medical Center for treatment. He arrived on Monday and left on Wednesday, just hours before Britney was brought there early Thursday morning.

[ All Access: Justin Chambers & Eva Mendes - Watch the Video ]