The crowd was thin to start, and even after Arian Grenier admitted to being single and open to a relationship, students continued to leave Graham Chapel, leaving only the first several rows occupied by the time he finished talking.

While he is most well known for his roles on HBO’s “Entourage” and “The Devil Wears Prada,” Grenier’s presentation centered primarily on his beliefs about environmental activism and SHFT.com, a website he co-founded to promote people and small businesses engaged in sustainable efforts. A segment of his presentation was devoted to videos shared on the website.

People started walking out of the Congress of the South 40 event after about 20 minutes, and by the halfway point, approximately half were gone.

But his appearance alone was enough to enthrall senior Kyle Bank.

“It was entertaining to be able to ask him a question and interact a little bit. I was totally starstruck,” Bank said.

Prior to playing a public service announcement about a plastic bag ban, Grenier praised Washington University’s own ban on plastic bags, currently in place in Paws & Go.

Grenier encouraged students to cultivate sustainable behaviors in their own lives. He expressed an understanding of students’ busy lives but encouraged them to focus on incorporating small, manageable actions into their daily routines.

“Your efforts must not be reactionary but deliberate and absolutely folded into your every day and must sustain themselves for a lifetime in order to be effective…You must let yourself understand the big picture, but don’t get distracted by it,” he said.

The exodus from the chapel only continued through the question-and-answer session that followed, started by 10 students who had submitted questions on Facebook.

The floor was then opened to the remaining audience members, who asked questions ranging from whether Grenier was single—he said he is—to what his ideal day would be.

Some of the questions seemed to come as a surprise to Grenier, who deferred a question about the craziest event that happened to him on the set of HBO show “Entourage” because he could not think of an appropriate answer on the spot. He eventually offered a tame anecdote about his co-star Kevin Dillon breaking his arm during shooting.

“You guys are going to get me in trouble,” Grenier said. “I thought I was going to come here and talk about the environment.”

Grenier also fielded a question about a possible “Entourage” movie. “If it doesn’t happen, I’ll give you a hundred bucks,” he promised a student.