The 33-year-old actor addressed rumors of his sexuality in a statement to People magazine on Thursday.
"I guess there have been a few questions about my sexuality, and I'd like to quiet any unnecessary rumors that may be out there," Knight's statement read. "While I prefer to keep my personal life private, I hope the fact that I'm gay isn't the most interesting part of me."
Knight plays Dr. George O'Malley on the popular ABC drama. A former stage actor, his television credits also include "CSI: Crime Scene Investigation" and "Law & Order: Criminal Intent."
Knight's "Grey's Anatomy" character, a bumbling, puppy-eyed surgeon, has long been in love with Dr. Meredith Grey (Ellen Pompeo).