Private Practice’s Kate Walsh posted a photo of herself and former costar Patrick Dempsey on what looks to be the Grey’s Anatomy set, and we’re wondering what the heck is going on.

Patrick Dempsey spoofs his character alongside other famous, fictional M.D.s Neil Patrick Harris (Doogie Howser), Donald Faison (Scrubs) and — surprise! — his Grey’s Anatomy ex-wife Kate Walsh.

Kate Walsh discusses Patrick Dempsey's 'hugely moving' cameo in 'Grey's Anatomy' season 17 — watch the video ...

For a blast from Kate Walsh and Patrick Dempsey's pasts, you can find the first 15 seasons of Grey's Anatomy and all six seasons of Private Practice streaming on Netflix now.

After being diagnosed with a brain tumor in 2015, actress Kate Walsh changed her life, living in the moment, and working less - basically having more fun.

Kate Walsh and Patrick Dempsey posted a selfie from what looks like the 'Grey's Anatomy' set, and fans are flipping out. See the picture, and get the details.

More than 16 years after Kate Walsh made her splashy “Grey’s Anatomy” debut as Dr. Addison Montgomery-Shepherd, the then-unmentioned estranged wife of Dr. Derek Shepherd (Patrick Dempsey ...

Kate Walsh Will Return to 'Grey's Anatomy' — See Ellen Pompeo and Patrick Dempsey's Reactions Kate Walsh confirmed she will be returning for an episode of Grey's Anatomy on May 5 ...

Her character, Addison Shepherd, was first introduced when the double board-certified OB/GYN appeared on the series trying to save her marriage to Derek Shepherd (played by Patrick Dempsey).

MORE: 'Grey's Anatomy' suspends production over COVID-19 concerns Dempsey, who left his lead role in season 11, even added some hand clapping emojis to Walsh's Instagram post featuring the scene.

Kate Walsh, who played Addison Montgomery alongside Patrick Dempsey's Derek Shepherd on early seasons of "Grey's Anatomy," talked on TODAY about if she'd return.