Janet Jackson loved “Thriller” before the world heard it. It came down to a little habit Michael kept with her.

Most families have a private ritual or two. Little things that never made the photo albums but stuck with you anyway.

The Jacksons had nine children, and Janet was the youngest. She was born in May 1966. Michael, born in August 1958, was the big brother who’d go on to become the King of Pop. When “Thriller” came out in late 1982, Janet was 16, and the two of them were still living under the same roof at the family home in Encino, California. Michael lived there from 1971 until 1988.

So years later, when Larry King sat down with Janet on CNN’s “Larry King Live,” he had a question few people on earth could answer the way she could. The transcript of that encore airing is dated March 16, 2008, and the talk turned to the 25th anniversary of “Thriller.”

Janet sounded like any proud little sister. “It’s huge. It’s big, number one everywhere. Good for him. Twenty five years, how fast did that go by?”

Then King went one step further, and her answer is worth hearing in her own voice.

Janet Jackson’s 2008 sit-down with Larry King

King asked: “When that came out, when it was recorded, did you think it would be what it became?”

She could have talked about sales or awards. She didn’t. She went straight back to her brother.

“I knew I loved it. I knew that I loved it. As a matter of fact, he played, as he always did when we were very close growing up, and every time he would complete a project, he would play the entire album. He had a great sound system in his car. We would sit in the car and we would listen to the album from front to back. I loved every song I heard.”

That was the ritual. Whenever Michael finished an album, he’d play Janet the whole record, start to finish, with the two of them sitting in his car.

To be clear, she wasn’t saying she heard it first. Producer Quincy Jones and the studio team had lived with those songs long before she did. But once the work was done, Michael wanted his kid sister to hear all of it, every song in order.

And look at the words she chose. “As he always did.” This wasn’t a one-time treat for “Thriller.” It was something he kept doing, project after project, while they were growing up.

Before it was the famous short film, the title song was just one track on the record he played for her, so here it is in full.

Michael Jackson’s “Thriller” short film

It took a long time for the two of them to share a song of their own. In the same interview, Janet said their 1995 duet “Scream” was “our first time ever working together since we were kids.”

But in a way she’d been part of his music for years before that. Every time he finished an album, she got to hear it start to finish.

Plenty of us remember sitting in the car with family and a favorite record. Michael Jackson’s version of that memory came with his little sister Janet, and the album they listened to went on to become the biggest of all time.