'Grey's Anatomy' star Kate Walsh accidentally reveals engagement

Kate Walsh recently revealed she is engaged -- seemingly accidentally -- on social media.

The "Grey's Anatomy" actress introduced boyfriend Andrew Nixon as "my fiancé" during a recent Instagram Live with her "Private Practice" co-star Amy Brenneman, in honor of the 15th anniversary of the show's premiere.

"Here comes the jungle cat, that is my fiancé," Walsh, who turns 55 on Oct. 13, told Brenneman, panning the camera over to Nixon as he walked in the door, smiled and waved.

"She just 100% outed your engagement," Brenneman said, referring to her pal's slip up.

"I did," Walsh responded. "I just outed our engagement."

Editor’s Picks

Ellen Pompeo discusses Katherine Heigl's remarks on 'Grey's Anatomy' schedule

Ellen Pompeo talks reuniting with Kate Walsh on 'Grey's Anatomy'

'Grey's Anatomy' actors reflect on key scene 15 years later

"Good Morning America" has reached out to Walsh's representative for comment.

Walsh was previously married to Alex Young from 2007 to 2010.

Those missing Walsh on "Grey's Anatomy" will be pleased to hear that, after reprising her role as Dr. Addison Montgomery in three episodes last season, she'll be back in a recurring role for season 19, premiering tonight, Oct. 6, on ABC.

Addison will make her first appearance this season in the third episode.

Walsh first appeared as Addison in the "Grey's Anatomy" season 1 finale and stayed on through season 3 before leaving for her character's own series, "Private Practice." The spin-off lasted for six seasons, airing from 2007 to 2013.