Ellen Pompeo is ready to be a mom!

"She is so on top of it, and she is so excited and she is very sweet about it," Grey's Anatomy co-star Jessica Capshaw (Arizona) told Us Weekly at an event at the Byron & Tracey Salon in Beverly Hills on Thursday. "She is doing all her research."

Capshaw - who had her first child, Luke, in September 2007 - says she hasn't had to give any parenting advice to her pregnant co-star.

"She doesn't need any," the actress tells Us. "She is exactly the way that she should be about it, which is really excited and hopeful but at the same time really pragmatic and planning."

"I think that is the best way for her to be."

Ellen Pompeo, 39, announced in April that she and her music producer husband of a year and a half, Chris Ivery, are expecting their first child.

Capshaw - who stars as Dr. Arizona Robbins in the hit ABC series - doesn't know if her pregnancy will be written into next season's show, and she's equally unaware if T.R. Knight and Katherine Heigl will return (rhe two appeared to have died in the season finale).

"No one knows!" Capshaw says.

She adds: "[Show creator and executive producer Shonda Rhimes] is keeping it under wraps, and I think the best thing about that is she is the guardian of the gate. It's better that way. She doesn't even run the risk of it coming out because nobody knows."

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.