The 'Begin Again' helmer went on to call the actress 'nothing but professional' during the shoot.
Keira Knightley's Begin Again director has chalked his comments about her up to "shoddy behavior" and now he is apologizing.
James Carney spoke with Britain's Independent about working with the actress and said, "Keira's thing is to hide who you are and I don't think you can be an actor and do that." He also claimed he would never work with a "supermodel" again, prompting some of Knightley's other directors to come out in support of her.
Now, Carney has taken to Twitter to chide himself for the "petty, mean and hurtful" things he said. "I'm ashamed of myself that I could say such things, and I've been trying to account for what they say about me," he wrote.
WATCH: Keira Knightley's Broadway Debut Disrupted by Screaming Fan
"In trying to pick holes in my own work, I ended up blaming someone else. That's not only bad directing, that's shoddy behaviour, that I am not in any way proud of," he added. "It's arrogant and disrespectful. Keira was nothing but professional and dedicated during that film and she contributed hugely to its success."
Carney revealed that he also personally wrote to Knightley to say he was sorry.
In the initial interview, Carney claimed that he didn't want to "rubbish Keira," but continued, "It's hard being a film actor and it requires a certain level of honesty and self-analysis that I don't think she's ready for yet, and I certainly don't think she was ready for on that film."
Never Let Me Go director Mark Romanek fired back, tweeting that working with Knightley was "utterly spectacular," while Seeking a Friend for the End of the World helmer Lorene Scafaria chimed in, saying, "Keira was a joy to work w/. Present & easy & really, really good at her job."
In other Knightley news, the actress welcomed her first child with her husband, musician James Righton, last year. Find out her daughter's sweet name and how Knightley says motherhood has changed her life in the video below.