The Hunger Games: Catching Fire star talked about his embarrassing experiences during an interview on Live with Kelly and Michael on Wednesday.
"I was in her class – I would come in for the first part of it and leave half way through," he admitted about his school days back home in Australia.
"That must have been awkward," Michael Strahan commented.
"Ah, yeah, a little bit. You'd think it would be, wouldn't it?" Hemsworth, 23, replied. "You have your mom talk about sexual stuff, it's not a class I'd like to be in."
"Did she ever call on you or anything?" Kelly Ripa asked.
"I used to put my head down most of the time," he said. "We had this one time where we were given out cards of different sexually transmitted infections and you had to stand up and talk about the card and she picked me out of the whole room. It was like, 'Well, I have chlamydia … thanks for this, Mom. Good class.'"