Over 500 Broadway artists formed a united front against Patti LuPone after the actress hurled insults toward theater peers Audra McDonald and Kecia Lewis earlier this week.

An open letter reprimanding LuPone for being a “bully” and signed by many is circulating — and it directly addressed LuPone, 76, calling Lewis a “bitch” and insulting McDonald as “not a friend” in a recent New Yorker profile.

According to Playbill, the screed is addressed to powerful organizations including the Broadway League and the American Theatre Wing as well as “the greater theatre community.”

“Recently, Patti LuPone made deeply inappropriate and unacceptable public comments about two of Broadway’s most respected and beloved artists,” the letter stated in part, adding that LuPone’s comments were “degrading and misogynistic” and “a blatant act of racialized disrespect.”

“It constitutes bullying. It constitutes harassment,” the letter continued. “It is emblematic of the microaggressions and abuse that people in this industry have endured for far too long, too often without consequence.”

The letter further labeled LuPone’s comments as a “public affront to the values of collaboration, equity, and mutual respect” embraced by the theatre community and called the verbal insults a “pattern.”

“A persistent failure to hold people accountable for violent, disrespectful, or harmful behavior — especially when they are powerful or well-known,” it continued.

“This is not about differing opinions. It is about public actions that demean, intimidate, or perpetuate violence against fellow artists.”

The letter stated that the community will no longer tolerate “the normalization of harm in an industry that too often protects prestige over people.”

“We will no longer tolerate violence — verbal, emotional, or physical — against artists within our own community,” the letter declared, asserting that “if our industry is truly committed to equity, justice, and respect, then those values must be applied consistently, even when it’s uncomfortable. Especially when it’s uncomfortable.”

The letter’s signatories included Tony winners James Monroe Iglehart of “Aladdin,” Maleah Joi Moon of “Hell’s Kitchen,” and Wendell Pierce of “Radio Golf.”

Page Six reached out to reps for LuPone, but did not receive an immediate response.

LuPone’s scathing comments about Lewis, 59, challenged the actress’s self-professed status as a “veteran” in the industry in a recent social media post.

“Here’s the problem,” she told the New Yorker in the controversial profile. “She calls herself a veteran? Let’s find out how many Broadway shows Kecia Lewis has done, because she doesn’t know what the f–k she’s talking about.”

She added, “She’s done seven. I’ve done thirty-one. Don’t call yourself a vet, bitch.” The magazine noted Lewis had actually done 10 shows, while LuPone has done 28.

Her “not a friend” comment on industry rival McDonald came after working with the “Good Fight” actress, 54, on Broadway productions of “Sweeney Todd” and “Rise and Fall of the City of Mahagonny.”

When asked her opinion on McDonald’s turn as Mama Rose in the Broadway revival of “Gypsy,” she went silent for 15 seconds before turning toward the window and uttering, “what a beautiful day.”

McDonald, for her part, took the snub in stride and issued a non-confrontational response.

“If there’s a rift between us, I don’t know what it is,” the actress said in a preview clip shared via Instagram Thursday for a “CBS Mornings” interview.

“That’s something you’d have to ask Patti about,” McDonald continued. “You know, I haven’t seen her in about 11 years just because we’ve been busy just with life. So I don’t know what rift she’s talking about, but you’d have to ask her.”