Michael Jackson’s son opened the real “Thriller” theater. Then two guests walked out.

Every year around Halloween, Prince Jackson throws a night he calls “This Is Thriller.” Prince is Michael Jackson’s oldest son, and he holds it at a place that means something. The Palace Theatre in downtown Los Angeles is one of the spots where his dad filmed the “Thriller” video back in the early 80s.

This year’s night was Saturday, Oct 24.

The fans who got in knew they’d see “Thriller” things. Prince changes the format every year, so nobody walks in sure of what’s planned. That’s part of the fun. What they didn’t know was that two people were waiting backstage to surprise them.

A quick word on why Prince does this at all. The night raises money for his Heal Los Angeles Foundation, which helps kids and families around the city.

Now, the surprise.

According to MJVibe, the fan site that first reported on the evening, two guests walked out to join Prince on stage. The first was Jaafar Jackson. Jaafar is Michael’s nephew, and he plays Michael in the new movie “Michael,” the big biopic fans have been waiting on for years. The second was Juliano Valdi, the young actor who plays Michael as a boy in that same film.

The room, by all accounts, lost it.

The three of them sat and talked about the movie together, in the very theater where Michael once danced for the “Thriller” shoot. For a crowd of fans who grew up on his music, that’s about as good as a Halloween night gets.

If you want to understand why this tradition matters so much to Prince, he’s talked about it before. In this older sit-down he walks through what his Thriller Halloween party means to him and shows a bit of the place.

Prince Jackson explains his yearly “Thriller” Halloween tradition

The talk wasn’t the only thing that night. Fans got about an hour of footage from “Don’t Stop ‘Til You Get Enough: Making of Michael,” a behind-the-scenes look at how the biopic came together.

The First AME Church of Los Angeles Choir sang “Man in the Mirror,” which is a hard song to sit through dry-eyed in a room full of people who loved Michael. And the original “Thriller” short film played on the big screen, right where parts of it were shot.

So far MJVibe is the only place that’s written the whole thing up, and no full video of this year’s night has surfaced yet. Photos have started going around from the people who were there.

For now, the older interview above is the closest thing to being in the room with Prince on his favorite night of the year. Give it a watch and you’ll get why he keeps the doors of that old theater open every October.