Television host and science educator Bill Nye collapsed late Tuesday as he gave a presentation at the University of Southern California (USC), the Los Angeles Times reported.

According to a student who attended the lecture, Nye collapsed mid-sentence as he was walking toward the podium.

“Then after about 10 seconds, he popped back up with much gusto and asked everybody how long he was out for and went on with a story about how a similar thing happened to him that morning,” USC senior Tristan Camacho said, according to the Times.

Nye, 54, continued with the presentation but began slurring his words and stumbled against his laptop, according to Camacho, who said that when Nye first collapsed, students were “texting and updating their Twitter statuses” instead of going to Nye’s aid.

Nye refused the offer of a chair but was eventually removed from the stage. The Los Angeles Fire Department and USC’s department of public safety were called to the scene at Bovard Auditorium, but it was unclear whether Nye received medical treatment.

Nye is best known for hosting the “Bill Nye the Science Guy” television series, which originally aired from 1993 to 1997 and won multiple Emmy awards.