She and Alex Young got engaged in May after dating for just three months.
"We've been together since February," Kate Walsh, 39, told People at a poolside party for facialist Kate Somerville at the Beverly Wilshire hotel.
"I know. I'm literally living the dream. But you know when you know. I was not expecting it, so it's kind of amazing."
While Kate Walsh says she really loves "everything" about her fiancé, a production co-president at 20th Century Fox, she admits she's partial to his looks.
"He's pretty handsome," she said, adding with a giggle: "He's ridiculously handsome!"
It doesn't hurt that he's helping with wedding plans... in his own way:
"He's really great. He's there, but not in the way! He wants to contribute."
So, she's taken charge.
"You start getting into this and you don't want to be a cliché, but then suddenly you're like, 'I'm doing all this stuff!'"
Considering she's also preparing for her new series, Private Practice, which starts shooting in mid-July, her schedule must be packed.
"It's insane, yeah," she said. But she has a mantra that keeps her centered when it comes to wedding planning: "Delegate, delegate, delegate!"
To help her manage things, she and Alex Young are taking a quick vacation.
"We're going to a balmy island," she said. "This is my getaway, and as soon as I come back we just hit the ground running."
No wedding date is officially set for Kate, or Grey's Anatomy leading lady Ellen Pompeo and fiance Chris Ivery. Katherine Heigl, the third engaged cast member, plans to wed musician Josh Kelley right before Christmas. We're happy for all three of these terrific actresses.