The 48-year-old actress congratulated Oh, her former Grey's Anatomy co-star, in a tweet Friday following the star's landmark Emmy nod for the BBC America series Killing Eve.
Oh had reacted to her nomination in a tweet Thursday while spending time with actress Michelle Krusiec. Pompeo re-tweeted the post.
"Yes!!! So incredibly happy for @IamSandraOh who deserves this more than anyone," she added. "No one can touch this girls dedication to story telling or her talent."
Oh plays Eve Polastri on Killing Eve, and is up for Best Actress in a Drama Series for the role. She is the first woman of Asian descent to be nominated in the category.
Pompeo portrays Meredith Grey on Grey's Anatomy, while Oh played Cristina Yang in Seasons 1 through 10 of the ABC media drama. Oh discussed the possibility of her return in an interview with Variety in April.
"I'm just going to say no. I'm just going to put that down there because it's been four years since then, and I've really got to try and create much more of a separation," the actress explained. "Even though I could just talk on and on and on about that show what I feel like I learned from it and continue learning from it."
"It was so special, lightning in a bottle that's lasted for over a decade," the added.