Cohen, in a draft of his opening statement opening statement, claimed his former boss didn't exactly hold his eldest son in the highest regard.

"Mr. Trump had frequently told me and others that his son Don Jr. had the worst judgment of anyone in the world," Cohen will say, according in the prepared statement.

The remark comes in a section where Cohen discusses the June 2016 Trump Tower meeting between high-ranking members of the Trump campaign, the president's inner circle and Russians. Trump Jr. helped arrange the meeting, where the Trump camp believed it would be getting damaging information on then-presumptive 2016 Democratic presidential nominee Hillary Clinton.

Cohen claims, according to the draft of his remarks, that Trump Jr. told his father about the meeting: "Something clicked in my mind. I remember being in the room with Mr. Trump, probably in early June 2016, when something peculiar happened. Don Jr. came into the room and walked behind his father's desk – which in itself was unusual. People didn’t just walk behind Mr. Trump’s desk to talk to him. I recalled Don Jr. leaning over to his father and speaking in a low voice, which I could clearly hear, and saying: 'The meeting is all set.' I remember Mr. Trump saying, 'Ok good...let me know.'"

Cohen said Trump Jr. "would never set up any meeting of any significance alone – and certainly not without checking with his father."

Trump Jr. responded in a Wednesday morning tweet, saying: "Only Democrats could hate someone so much that they would try to disrupt nuclear peace talks with testimony from a convicted felon."