Less than a week ago, the campaign of Republican gubernatorial candidate Charles Herbster was thrown into turmoil after multiple women accused him of inappropriate touching.
The allegations have been denied by Herbster.
Less than two weeks before the primary election, the only other person slated to speak at the rally is Herbster.
The announcement sent by Trump's political action committee, Save America, on Tuesday morning said that the 67-year-old agricultural business executive was a special guest speaker.
The announcement came five days after a bombshell report from the Nebraska Examiner, in which numerous women, including a Republican state senator, accusedHerbster of touching them during events in recent years.
The Examiner reported that Julie Slama said that she was touched without her consent byHerbster in the middle of a crowded ballroom during a Republican Party dinner in 2019.
Six other women, who spoke to the news outlet on condition of anonymity, accusedHerbster of grabbing their buttocks over their clothes while posing for photos with him. According to the Examiner, another woman said thatHerbster kissed her forcibly.
He suggested that the report had been pushed by his political enemies.
I have respected and empowering women to run my company, my farm and now my campaign. My integrity has never been challenged in this way. The establishment has a stranglehold on this state and do they stoop to lies this large, said Herbster in his statement.
The political establishment is lying about him because they are scared of losing power, he said.
When CNBC asked if he had discussed the controversy with Trump, the campaign did not respond immediately. A spokeswoman for Trump did not respond to a request for comment.
Slama, who was 22 years old at the time of the alleged incident, said in a statement that the report was true.
Slama said that she had been groped at a political event early on in her political career, and that she had been referring toHerbster's alleged actions when she spoke before the Nebraska legislature in February.
Her latest statement said she was not going to lie and say it didn't happen.
Two days before the Examiner reported, polling showedHerbster locked in a competitive Republican primary fight with University of Nebraska Regent Jim Pillen and State Sen.
The Examiner's report was "beyond horrible" and "Urged Herbster to beg forgiveness of the women he has preyed on."
The statement said that sexual assault is criminal behavior and should disqualify anyone from elected leadership.
Theresa Thibodeau,Herbster's former running mate and current primary rival, told the Examiner that she was disgusted by the accusations, but had not seen any of them.
She was troubled by the continued involvement of Lewandowski in the campaign. Last year, it was reported that Lewandowski was accused of making sexual advances toward a GOP donor.
Donald Trump Jr., the oldest son of the former president, was in Nebraska last week.