Katherine Heigl Once Called ‘Grey’s Anatomy’ Co-Star T.R. Knight Her ‘Best Friend’ — Are They Still Friends?

Grey’s Anatomy stars Katherine Heigl and T.R. Knight played best friends on screen. This translated to a fan-adored friendship in real life. But things change over the years. Are the actors still close?

Katherine Heigl and T.R. Knight starred in ‘Grey’s Anatomy’

T.R. Knight as George O'Malley and Katherine Heigl as Izzie Stevens on 'Grey's Anatomy'
T.R. Knight as George O’Malley and Katherine Heigl as Izzie Stevens on ‘Grey’s Anatomy’ | Danny Feld/Walt Disney Television via Getty Images

Heigl and Knight both began starring in Grey’s Anatomy in the pilot. They portrayed Izzie Stevens and George O’Malley, respectively — interns who befriend Meredith Grey while working at Seattle Grace Hospital. They’re the first two roommates to move into Meredith’s house.

Izzie and George quickly became best friends. They shared many life-changing moments together, eventually leading to their short-lived romance in seasons 3 and 4, which didn’t go over well with fans. It took them some time, but after some time, George and Izzie salvaged their friendship.

Though Heigl understands why fans didn’t love George and Izzie as a couple, she enjoyed the experience of filming it. “I was really excited about it in the beginning because, obviously, I got to work more with my best friend and that’s awesome,” she told Entertainment Weekly in 2010.

George died in season 5, while Izzie left during season 6

Not long after getting back to their friendship, George and Izzie faced more trouble. In Grey’s Anatomy Season 5, Izzie gets cancer. During one of her surgeries, she flatlines and sees George in a uniform. Her friend, who recently quit to join the Army, got hit by a bus. Izzie recovers, but George dies in the series finale.

Izzie struggles to get back into the swing of things in season 6. She goes back to work but is later fired. Izzie leaves town, leaving Alex distraught. She later returns and tries to win him back, but he ends things, and she leaves for good. Izzie’s story doesn’t get a real end until she’s mentioned in Alex’s letter in Season 16.

Heigl stood up for Knight after the Isaiah Washington incident

T.R. Knight and Katherine Heigl at the PEOPLE/Entertainment Industry Foundation SAG Awards party.
T.R. Knight and Katherine Heigl at the PEOPLE/Entertainment Industry Foundation SAG Awards party. | E. Charbonneau/WireImage for People Magazine

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Heigl told EW that she left Grey’s Anatomy to spend more time with her family. But her sudden departure came after a handful of incidents that caused media outlets to paint her as “difficult.” The actor’s outspoken nature may have caused her problems in her career, but it helped in at least one personal relationship.

At the 2007 Golden Globes, Isaiah Washington, who portrayed Preston Burke in Grey’s Anatomy, addressed rumors that he called Knight a homophobic slur. Heigl later told Access Hollywood (via People) Washington “needs to just not speak in public,” adding, “T.R. is my best friend. I will throw down for that kid.”

She addressed the incident again in 2010. Though Heigl was worried she embarrassed Knight, he reassured her, saying “he was no grateful because no one had ever stood up for him that way before.” She added, “that is a proud moment for me [and] I don’t regret it. And I’m just so grateful that my friend doesn’t regret it.”

Proof Heigl and Knight may not be friends anymore

After their time on Grey’s Anatomy came to an end, they remained in touch. Heigl attended Knight’s 2013 wedding. And in 2015, a Twitter user asked Heigl, “are you and @TR_Knight still friends??” The actor replied, “Of course and we always will be! He’s the best. A wonderful friend and a special person to me.”

However, it’s been years since they had an interaction. Heigl and Knight don’t follow one another on Instagram. But regardless, Heigl “is proud” that she “stood up for her close friend twice,” according to an Entertainment Weekly source after Washington reignited their feud in 2020.