Okay, so you know how sometimes grown-ups watch movies with other grown-ups doing things that we don't do in real life? AV idols are actors who appear in movies like that, but they're from Japan.
The AV stands for Adult Video – and that’s just a fancy word for movies that show grown-ups doing grown-up things. The actors who appear in these movies become very popular and are often called AV idols.
Just like in regular movies, these actors take on different roles and tell stories, but in AV movies the stories usually involve adults doing things that we're not supposed to do when we’re young. But it's just pretend – like when we play make-believe!
AV idols usually have a special look, like nice hair and makeup, and they dress up in pretty clothes or costumes. This makes them more fun to watch on screen. Lots of people like to watch AV movies because it's exciting and makes them happy, but it's only for grown-ups so you have to wait until you're older to watch them.