Now it's up to ABC to decide if that spinoff is justified.
From a numbers standpoint, it's an easy decision. Last Thursday's two-hour episode, "The Other Side of This Life," in which Addison left Seattle Grace for a new start and new pals in Santa Monica, Calif., drew over 21 million viewers.
But from a critical standpoint, it's, well, a Grey area.
The spinoff was greeted less-than-enthusiastically by many Grey's Anatomy fans, who voiced their displeasure on online forums and message boards.
"It was the first time that Grey's has been on ABC that I went to bed before it was over," one fan wrote.
"Addison will never make it on her own show. The characters were not very good on the new show and it was annoying to watch."
"Awful is an understatement," replied another. "I had two phone calls from friends after the first hour and we all had the same opinion - it sucked."
ABC officials, so far, have been quiet regarding the spinoff, the fate of which will be clear Tuesday when ABC unveils its upcoming fall schedule at its "upfront" presentation.
One network insider yesterday described ABC officials as "thrilled" with the show's ratings and "very happy" with its content, which was supplied by show creator Shonda Rhimes (who wrote the two-hour episode).It was, in effect, ABC's reward to Shonda Rhimes for creating a ratings powerhouse - but at the risk of alienating some Grey's Anatomy viewers.
"If they're going to do a spinoff, they should do it now while the iron is hot," analyst Marc Berman of Mediaweek tells the New York Post.
"The thing about taking Kate Walsh off Grey's Anatomy is that you're not losing a lot ... it's taking a secondary character and building a show around that person.
"As long as Shonda Rhimes doesn't stretch herself too thin it's a good idea - and I hear she has a whole new crew [for the spinoff] and a show runner."
And, to be fair, not every fan was put off by Addison's venture into new territory.
"I have to say I loved the show so much I have watched it 3 times already," writes one fan in a typical "loved it" posting.
"Their ploy worked - I will now be looking for this spinoff to start because I think it will be just a good as Grey's."