Walsh's rep and an ABC spokesperson confirmed to E! News that the Private Practice star is returning to Grey Sloan Memorial as Dr. Addison Forbes Montgomery. According to Deadline, Walsh will appear in "multiple episodes," alongside Ellen Pompeo and the rest of the cast.
The 53-year-old actress celebrated the news on social media, captioning a silly dance video, "It's really happening. Dr. Addison Montgomery will see you shortly."
In the clip, she mouthed the words to Emma Roberts' iconic American Horror Story: Coven scene, in which Madison Montgomery said, "Surprise, bitch. I bet you thought you'd seen the last of me."
In a more serious video shared to Shonda Rhimes' Shondaland accounts, Walsh shared, "It feels so good to be home again and joining Shonda, Ellen and the rest of the incredible cast on season 18 of Grey's Anatomy. Just wait till you see what she's got in store for you."
Fans of the medical drama celebrated the news of Addison's return, including Pompeo, who stole Addison's estranged husband, Derek Shepard. "Let's give them what they want... quality tv drama," the Meredith Grey actress commented on Instagram.
After Derek and Addison eventually split, the world-renowned gynecologist went to California to open her own Private Practice and start a new life post-divorce. The show, which also starred KaDee Strickland and Taye Diggs, went on for six seasons.
While Addison had a whole new life going for her in Los Angeles, she made the occasional guest appearance on Grey's Anatomy. Walsh's last guest role in the ABC drama was in the season eight episode "If/Then," in which Meredith reimagines what her life would look like if she hadn't made certain choices, including falling in love with Patrick Dempsey's character.
Speaking of Dempsey, he and a slew of other former Grey's Anatomy stars returned to the show for a dramatic season 17.
Those reunions were short lived, but season 18 more than makes up for Derek's brief appearance and a handful of exits with the return of Addison and Kate Burton's Ellis Grey. Additionally, The O.C.'s Peter Gallagher is set to make his Grey's debut.
Tune in to the season 18 premiere of Grey's Anatomy when it airs on Thursday, September 30 at 9 p.m. on ABC.