“Blue Bloods” costumer Trenena “Trina” Patterson is accusing the show’s top costume designer, Michael Woll, of race discrimination and unlawful termination in an explosive lawsuit she filed against him and ViacomCBS in March.

The suit claims Woll asked a co-worker, “Why would you hire that little black girl? She looks like a hot ghetto mess” when Patterson was first hired.

Later, “he was promoted from supervisor to costume designer. He would yell and curse at me so bad that I was often reduced to tears,” she told Page Six.

She said he went ballistic after she escorted an actress to the wardrobe truck without his permission. “We were on Fifth Avenue and he yelled at me in front of everyone. He shouted, ‘You’re f–king incompetent. Shut the f–k up. You’re f–king lazy.’ I teared up and he kept going,” she said.

Woll called her “racially motivated epithets such as: idiot, lazy and incompetent on a weekly basis,” according to the suit.

Patterson, who is African-American, says Woll also criticized her for wearing her hair in braids and scarves around her head. “He would call [the wraps] do-rags. He’d ask about the texture of my hair. Once when I wore it straight, he said, ‘She’s being a slut today.’ He’d also speak to me in stereotypical black voices and ask things like, ‘Do your kids have the same father?’ ” she recalled.

“It’s disrespectful. It’s like, ‘I can’t call her [the N-word] because it’s a direct slur, but I can make jokes about hair, weight, baby-daddies and do-rags.’ I complained to my direct supervisor at the time, but [Woll] was her boss. She felt very uncomfortable.”

Patterson finally stopped engaging with him and believes it cost her her job. “I didn’t want to be the joke anymore. Small talk left me open to his racial and sexist jokes.” Patterson’s suit alleges that after she complained, her hours were cut and she was then fired.

Reps for CBS and Woll did not comment.