Credit: Kevin Winter/Getty Images Photo: Kate Walsh and Amy Brenneman

Fans of Shondaland and period dramas are likely thrilled to see Private Practice star Amy Brenneman show up on The CW's Reign as Mary's mother and the acting regent, Marie de Guise — but the 49-year-old actress tells E! Online that the part was supposed to go to her Private Practice co-star!

"Kate Walsh [Addison Montgomery] was going to do it. It wasn't really on my radar much, and then Kate, Brad [Silberman, Amy's husband an an executive producer of Reign] and I all went out — [at] maybe the end of the summer, beginning of the fall — and she was like, 'I love the show,'" Amy recalls.

"They didn't get very far with it because she's involved with some projects that … wouldn't let her out, essentially. So I called her up. I was like, 'Oh my gosh — I'm sloppy seconds!'"

But the Grey's Anatomy alum was happy to bequeath the part, retweeting Brad's announcement of Amy's March 6 Reign debut and adding, "Go Amy!"

Meanwhile, Reign exec-producer Laurie McCarthy couldn't have nicer things to say about the replacement: "We've been waiting for just the right moment, and the actor, to introduce Mary's mother … Amy Brenneman's talent, strength, and beauty illuminate even the darker corners of Marie de Guise."

Now, much as we love Amy, if Kate had to give up the part to one of her TV colleagues, we would have loved to see how Taye Diggs could fit the role! Or Patrick Dempsey, for that matter!

Source: E! Online

Dan Clarendon is an assistant editor at Wetpaint Entertainment. Follow him on Twitter and Google+!