Kate Walsh: "Private Practice" finale will be "dramatic, crazy"

(CBS) Kate Walsh has a lot going on these days - she's got a new movie role in the works, "Private Practice" is finishing up its fourth season and she's heading to Churchill Downs for this weekend's Kentucky Derby.

The actress will be hosting a suite for Mott's Garden Blend during the event, and told us she was excited for all the hats and horses.

"We're going to be making cocktails and mocktails and then we're going to watch the horses," she said Wednesday. "It's such a massive American tradition and I'm excited to get to participate in it. It's something I've always wanted to do."

And as for her Derby hat? "It's really beautiful. I've actually only seen pictures of it because it's coming in from LA and I'm not there yet. But I hope it will fit and look fabulous."

Walsh said she's excited for fans to see how this season of "Private Practice" wraps up.

"I feel like this is our strongest season yet," she said. "This show just keeps getting better and better. The last new episodes for the season are just so strong - and very dramatic, crazy - there's a lot in store. So I'm really excited about them."

Walsh said she feels protective of Addison Montgomery, but trusts "Grey's Anatomy"/"Private Practice" creator Shonda Rimes and the show's writers with the character.

"[Rimes] has got my back, she's got Addison's back, she has all of the characters' backs," she said. "I think one of the great things that Shonda does is write really endearing, flawed, compassionate characters, that are deeply interesting and misguided at times. And, you know, kind of fabulous."

When asked about Benjamin Bratt joining the show during the season finale, she stayed mum on details about his character but had high praise for the actor.

"I can't tell you [who Bratt will play]. But he's spectacular, I can tell you that," she said. "He's a really amazing guy. No one knows a lot, in terms of who he's going to be - including me. But I can tell you that he makes an appearance."

The actress is an avid Twitter user, who shares stories and chats with fans (she says she'll also be tweeting from the Derby suite). It's something that she was turned onto by Rimes and her "Private Practice" co-star Amy Brenneman.

She recalled, "Shonda and Amy kept tweeting and it's like 'Ah, I can't go there, it's not who I am.' And now, I'm totally addicted. I love it - it's fun to be able to just tell your little stories but also have contact with fans, in a way that's 140 characters or less... It's like a modern-day salon. You get to keep in touch with people and banter. So, it's fun."

Walsh also has a new movie role in the works - when we spoke, she couldn't give details because the deal was being finalized, but shared that the film is a "coming of age story" adapted from a popular book.

"It's a great project, I'm thrilled. It's the only thing I wanted to do," she said." I'm just really super excited about it."

"I feel like I have a pretty charmed life," she added. "I get to host the Mott's Garden Suite at the Kentucky Derby and I can wear a pretty hat, and watch horse races and then go do a movie. So I'm pretty thrilled."