Rep. Mark Walker, R-N.C., called for Jerry Falwell Jr. to step down as the president of Liberty University after he posted a photo on Instagram in a yacht with his pants unzipped, with his arm around a woman. Walker, the Vice-Chair of the House Republican Conference, is also a pastor with ties to the university.

“Jerry Falwell Jr’s ongoing behavior is appalling. As a Music Faculty Advisory Board Member and former instructor @LibertyU, I’m convinced Falwell should step down,” Walker tweeted. “None of us are perfect, but students, faculty, alumni and @LUPraise deserve better.”

Falwell, 58, apologized for the photo on Wednesday in a radio interview, saying it was “just in good fun.”

“I’m gonna try to be a good boy from here on out,” Falwell said. He claimed the woman in the photo was his “wife’s assistant.”

Liberty University has strict rules for its students, banning dancing, sex outside of marriage and R-rated movies. The university was founded in 1971 by Falwell’s father, the televangelist and conservative activist Jerry Falwell Sr.

Falwell Jr. graduated from Liberty University in 1984 and later earned his law degree from the University of Virginia. He is married with three children.

Falwell Jr. is a staunch ally of President Donald Trump. He has described Trump as “America’s blue-collar billionaire” and “one of the greatest visionaries of our time.”