Millie Bobby Brown reveals she 'didn't even know what a record player was' before 'Stranger Things'

— -- In honor of Halloween, the cast of "Stranger Things" dropped by "Good Morning America" to celebrate the release of the show's new season on Netflix.

Since its Oct. 27 premiere, the show has proven to be a phenomenon -- producing millions of tweets from fans and setting a record for the most tweets for a streaming show on its opening weekend.

"It's just starting, definitely going to get bigger," said Gaten Matarazzo, who plays Dustin.

"It's amazing," said Caleb McLaughlin, aka Lucas Sinclair.

For Halloween, the cast said they usually spend the holiday trick-or-treating together.

"We are really last-minute," said Millie Bobby Brown. "Last year, I knew five minutes before. We cut up our costumes because they wouldn't fit us. They were a size 5, for a 5-year-old."

Season 2 introduced fans to some new characters, including Sadie Sink, who plays Max.

"It's very exciting," she said. "I love them and they're my best friends, so it's great."

Sink said before joining the show, she had never set foot on a skateboard.

"I would do like 3-hour lessons every day for two months, I think," Sink admitted.

The actors spoke about what it's like portraying kids living in the '80s.

"I think that era is so exciting and different for us," said Brown. "I was born in 2004, so I'm definitely very new to it. I feel like going onto set and seeing the bikes, I didn't even know what a record player was."

Matarazzo said he was familiar with the decade before landing his role on the series.

"I'd watched all the movie, I listened to that music," he said. "That's the music my dad listens to ... the Clash, the Smiths, the Talking Heads, he introduced me to all of it so I was already a fan. My grandparents had a record player in their house."

Season 2 of "Stranger Things" is streaming now on Netflix.