Miley Cyrus was one of the few people in her generation to not see any of the 'Harry Potter' movies ... even though she attended one of the series' premieres with her dad, Billy Ray.

Because she fell asleep!

Cyrus revealed to BBC radio DJ Nick Grimshaw (via ABC 23), "I had to go to the premiere and then I slept once I got in. I walked the carpet and I made my dad come with me and I literally laid down," she laughed. "He's like, 'You cannot do this at the theater right now! You're at the premiere, the actors are sitting right there,'" she said. "I'm like, 'I can't do it, I'm exhausted! I don't know what's going on because I haven't seen the other ones.' I've only seen the first one."

It turns out that Cyrus' mom, Tish, didn't allow her to see any of the previous Potter films because she thought they were evil. "My mom wouldn't let me watch it when I was a kid. She said it was witchcraft, she said it was dark," Cyrus admitted. "She didn't know what I was gonna turn out to be! My mom had high hopes. She thought Harry Potter was gonna be the worst!"