Forget killing off a character.

Grey's Anatomy just stunned the television world by confirming it was bringing back a character.

Oh, yes, folks... Kate Walsh is coming to Seattle!

The actress -- who made her Grey’s Anatomy debut as Dr. Addison Montgomery way back on Season 1 finale in 2005 -- will return to the medical drama for a multi-episode arc on Season 18.

Representatives from ABC confimed the unexpected news on Thursday evening, although they did not give specifics about Addison’s storyline.

Walsh, meanwhile, later shared the bombshell herself in a video posted on the Grey's Anatomy Twitter page.

"Well, well, well, would you look who it is.

"That's right, my loves, Dr. Addison Montgomery is coming back to Grey Sloan Memorial Hospital and I'm so excited to be home again joining Shonda, Ellen and the rest of the incredible cast," Walsh says in the footage.

She's referring here, of course, to series creator Shonda Rhimes and star Ellen Pompeo.

Dr. Montgomery was the first wife of Patrick Dempsey's Derek Shepherd, shattering Meredith's world to conclude Season 1 by strolling into the hospital and announcing she was married to Meredith's then-boyfriend.

Following Season 3, Rhimes spun Addison off and gave Walsh her very own drama, Private Practice, which aired from 2007 through 2013.

Walsh has more recently appeared on such streaming hits as The Umbrella Academy and Emily in Paris.

"This season — 18, whew! — Just wait until you see what she has in store for you.

"The new season premieres September 30 on ABC," Walsh added in her video yesterday.

Walsh isn't the only former star who will return in the upcoming season, as Kate Burton will reprise her role as Meredith's mother, Dr. Ellis Grey, on at least the upcoming premiere.

Ellis, of course, is dead.

Last season, other late characters -- such as T.R. Knight's George, Chyler Leigh's Lexie and Dempsey's Derek -- were revived in order to interact with Meredith on a fantasy beach she visited while in a Coronvirus-related coma.

On the flip side, meanwhile, Giacomo Gianniotti and Jesse Williams will NOT appear on Season 18.

In May, following what seemed like an endless delay, ABC renewed Grey's Anatomy (and Station 19) for what many observers assume will be the show's final season.

“The writers, directors, casts and crews of Grey’s Anatomy and Station 19 worked so hard to bring these shows to life this past season,” said executive producer Krista Vernoff in a statement at the time.

“Keeping each other safe on set while paying tribute to the front-line heroes and first responders has been a challenge and a privilege.

"I’ve been truly blown away -- particularly by our tireless crews -- as they reinvented the TV-making wheel."

Concluded the showrunner this spring:

"Thank you to ABC and ABC Signature for the support and extraordinary partnership through this unprecedented season.

"We are so grateful for the opportunity to tell more stories."

After all these years on the air, Grey’s Anatomy continues to dominate as ABC’s highest rated and most watched scripted series, averaging a 1.1 demographic rating and 5.3 million weekly viewers.

Will this truly be the final run for one of the most successful program's of all-time?

We can't say for certain.

But KATE WALSH IS COMING BACK AS ADDISON MONTGOMERY!

That much we can state for the record, and we really can't believe it.