Donald Trump has gone ahead and done it now.
Sure, he's made fun of celebrities in the past, from Alec Baldwin to Arnold Schwarzenegger and pretty much anyone not named Vladimir Putin.
But now the President-Elect has laid into true Hollywood royalty.
He's dared to say mean things about Meryl Streep.
On Sunday night, Streep used her platform at the Golden Globe Awards to talk about Trump; specifically the time in 2015 when he very clearly mocked a disabled reporter.
In accepting the Cecil B. DeMille Award, the veteran star refused to call Trump out my name; she simply referred to him as “the person asking to sit in the most respected seat in our country."
She said she was horrified and "stunned" by Trump's performance during a speech when he impersonated the handicap of New York Times investigative reporter Serge F. Kovaleski.
“It kind of broke my heart, and I saw it, and I still can’t get it out of my head because it wasn’t in a movie,” Streep said, adding:
“It was real life. And this instinct to humiliate when it’s modeled by someone in the public platform by someone powerful, it filters down into everybody’s life because it kind of gives permission for other people to do the same thing.”
In a conclusion that was cheered by her fellow stars on Twitter not long after it was uttered, Streep then said:
“Disrespect invites disrespect. Violence incites violence. The powerful — use definition to bully others, we all lose."
You can watch Streep's Golden Globe Awards speech below:
Naturally, Trump could not sit back and let these insults land, unanswered.
It is literally impossible for him to do so.
Initially, rather than Tweet about Streep's scolding, Trump called The New York Times and told the newspaper he was “not surprised” that he was attacked by “liberal movie people."
He also made a point of noting that Streep often stumped for Hillary Clinton on the campaign trail and called her a "Hillary lover."
Not so rough by Trump's standards, really.
But then he jumped on Twitter.
"Meryl Streep, one of the most over-rated actresses in Hollywood, doesn't know me but attacked last night at the Golden Globes," he wrote in one of three messages, expounding as follows:
"She is a..... Hillary flunky who lost big. For the 100th time, I never "mocked" a disabled reporter (would never do that) but simply showed him....... "groveling" when he totally changed a 16 year old story that he had written in order to make me look bad.
"Just more very dishonest media!"
You may go ahead and debate whether or not you think Meryl Streep is overrated.
(Go ahead and debate whether Hamilton is overrated, too, while you're at it, another one of Trump's assertions).
But there doesn't seem to be much debate over whether or not Trump mocked Kovaleski, who suffers from arthrogryposis, a condition which limits the use of his arms.
Watch the portion of Trump's 2015 speech in question below... and then try to defend him: