At an event promoting his new book, Donald Trump Jr. was heckled off the stage—not by liberal protesters but by conservative supporters of his father, the Guardian reports.

Trump Jr. was at the University of California, Los Angeles, on Sunday to talk about his new book, Triggered, when the disruption occurred. Attendees of the event were upset after they learned that the businessman wouldn’t be participating in a QA session about his book.

“QA! QA!” the audience began to chant. Trump Jr. tried to calm the audience, but they weren’t having it.

Trump Jr. was accompanied on stage by Kimberly Guilfoyle, the lawyer and journalist who is reportedly also Trump Jr.’s girlfriend. “You’re not making your parents proud by being rude and disruptive,” Guilfoyle told the audience. Soon after that, the pair exited the stage.

The Washington Post reports that Guilfoyle also questioned the romantic appeal of those who were shouting at Trump Jr. “Let me tell you something, I bet you engage and go on online dating because you’re impressing no one here to get a date in person,” she said.

Triggered became a bestseller shortly after its release last week. As of Monday afternoon, it was the No. 3 most popular book on Amazon.

The book has also drawn mockery from critics of the Trump administration. Last week, the comedy duo the Good Liars replaced the covers of some of Trump Jr.’s books at a New York bookstore with ones titled Daddy, Please Love Me: How Everything I Do Is to Try to Earn My Father’s Love.

Michael Schaub is an Austin, Texas–based journalist and regular contributor to NPR.