Washington and Paltrow both attended the Spence School, an all-girls private school, in New York, but were several grades apart.
"In high school, a few years difference makes a big deal," Washington said. "She was a senior when I was in junior high school. Even back then, she was Gwyneth Paltrow."
Washington said Paltrow played Titania, the queen of the fairies, in A Midsummer Night's Dream.
"She was the queen, of course," the star said. "I was one of the fairies. The middle schoolers were allowed to audition for the fairies."
"We had one amazing show together," she added.
Washington and Paltrow previously discussed their school days during a live episode of The Goop Podcast in October.
"I was in an a capella singing group called Triple Trio," Paltrow recalled. "We were holding auditions because a bunch of us were graduating. In walks Kerry Washington ... this beautiful eighth grader. So confident. She opened her mouth and the most exquisite voice came out."
Washington said she still enjoys singing, but mainly does so in private.
"In some ways, weirdly, I think singing is even more personal to me than acting," she explained.
Washington most recently starred in a Netflix adaptation of American Son, based on the Broadway play of the same name. She said on Today in October that the film can help start conversations about race.