A Cornell University senior stripped to her bra and underwear during her thesis presentation — and got two dozen others to join in — to protest her professor’s contention the week before that her clothing was inappropriate.

Letitia Chai led the revealing demonstration Saturday during her “Acting in Public: Performance in Everyday Life” class to stand up “against oppressive beliefs,” she said in a Facebook Live video of the event.

It came days after her professor, Rebekah Maggor, questioned whether the denim cutoff shorts Chai was wearing during a test run of the presentation were too short.

“The first thing that the professor said to me was ‘is that really what you would wear?” Chai wrote in a Facebook post about the incident. “The professor proceeded to tell me, in front of my whole class, that I was inviting the male gaze away from the content of my presentation and onto my body,” she wrote.

“I think that I was so taken aback that I didn’t really know how to respond,” she told the Cornell Sun.

Some students stood up for her, telling the professor she was the one being inappropriate and questioning her perception of men, but one international student sided with the teacher, saying it was Chai’s moral obligation to dress more conservatively.

“Am I morally offending you?” Chai said she asked the student, with tears of rage in her eyes, before storming out of the room.

The professor then came out to ask what her mother would think of her clothing, adding that she had a daughter she worried about, Chai wrote.

“My mom is a feminist, gender and sexuality studies professor. She’s fine with my shorts,” Chai said she responded.

When the professor asked what Chai was going to do, she responded, “I’m going to give the best damn speech of my life.”

That night, she wrote a Facebook post about the incident inviting the public to her thesis presentation on Saturday morning, and asking them to wear their favorite underwear, “in solidarity with anyone who has been asked to change how they look to make other people feel more comfortable.”

Her presentation was livestreamed and even her parents were watching from Korea, she said.

In the video, Chai said she stood with people who have been asked to “question themselves” based on people’s perception of their appearance, while holding back tears.

Then she stripped to her Uniqlo bra and underwear, and about 28 of the 44 people in the room joined her.

Her professor told The Sun that she doesn’t tell her students what to wear or what is appropriate dress, but “I ask them to reflect for themselves and make their own decisions.”

Following the initial response to Chai’s post about the classroom incident, 11 of the 13 other students in the class issued a statement saying they supported Chai’s protest but not her version of what happened.

They wrote that while there was “an error in phrasing” on the professor’s part, she was just trying to impart the importance of professionalism in public speaking situations.

“[Maggor] is a gift to Cornell,” the statement read, stating that the students felt Chai’s post did not “adequately represent [Maggor’s] past and continued advocacy for women and minorities” and that Maggor had “apologized on more than one occasion.”