Former Grey's Anatomy star TR Knight married his boyfriend Patrick on Friday, Oct. 4, sources confirm to Us Weekly Credit: Michael Tran/FilmMagic

TR Knight is a married man! The former Grey's Anatomy star has tied the knot with his longtime boyfriend Patrick, sources reveal to Us Weekly. The pair said "I do" on Friday, Oct. 4 in an intimate ceremony in front of family and friends.

"It [was] very small and quiet," an insider reveals to Us. One of the more famous faces to attend? Knight's former ABC costar and close friend Katherine Heigl and Kate Walsh flew in for the ceremony, the source says. No other details on the fete were immediately available.

Heigl tweeted about attending a wedding in upstate New York and shared a photo of herself posing with Walsh in a photo booth. "Having the time of my life at said wedding with @katewalsh [husband] @joshkelley Kate's amazing fella Chris & my girl Chey!" she captioned the funny photos.

Knight, 40, is currently playing the role of Mercutio in the Classic Stage Company's off-Broadway production of William Shakespeare's Romeo & Juliet in New York City. Knight's A-list costars in the classic tragedy include Elizabeth Olsen and William Hurt. "[The] cast wishes they could go too, but they all congratulated him," the source adds. Knight was noticeably absent from the Friday and Saturday showings to celebrate the big occasion.

Knight is best known for playing Dr. George O'Malley on Grey's from 2005 to 2009. He's also appeared on Law & Order: Special Victims Unit, The Good Wife and the film 42.