"I want you to know that I am ashamed that my network aired this disgusting racist ad," the outspoken advocate for the rights of marginalized people tweeted.
The ad, which Trump tweeted, focused on video of Luis Bracamontes, a Mexican man who was deported but returned and killed two California deputies.
"I'm going to kill more cops soon," Bracamontes boasted in court at that time. The video in the ad was accompanied by text that placed the blame for the death of the officers on Democrats.
"Democrats let him stay," the ad contends, falsely adding that Democrats "let him into our country" and "let him stay."'
In fact, George W. Bush was in office when Bracamontes entered the country for the last time. And it was Sheriff Joe Arpaio (a flunky of Trump's who was the recipient of a presidential pardon) who released Bracamontes "for reasons unknown."
The ad juxtaposes Bracamontes's boasting about killing officers with footage of immigrants flooding the United States border to stoke fears Trump and conservatives have drummed up over the migrant caravan from Central America currently making its way through Mexico.
CNN refused to run the ad, calling it "racist" and Fox News pulled it on Sunday. On Monday, NBC also pulled the ad accompanied by a statement from network officials.
"After further review we recognize the insensitive nature of the ad and have decided to cease airing it across our properties as soon as possible," NBC Universal said in the statement, according to The New York Times.
Since tweeting her embarrassment that NBC ran a racist ad, Messing has continually posted about getting out the vote. She's also tweeted about Trump's racism, gun violence, and voter suppression.