“Divergent” Author Recalls Time When Kate Winslet's Son Asked 'Why'd You Kill My Mom?' on Set (Exclusive)

Kate Winslet previously said she took the 'Divergent' role because she "wanted my kids to think I was cool"

Kate Winslet's son went directly to the source when curious about his mom's Divergent fate.

In the movie franchise, the Oscar winner starred as the villainous Jeanine, the leader of the Erudite faction who is determined to eradicate the Divergents, especially hero Tris, played by Shailene Woodley.

Veronica Roth, the author behind the books that inspired the films, tells PEOPLE that, while visiting the set once, Winslet's son Joe, now 19, asked her about killing off Jeanine in the second installment, Insurgent.

"The best thing that happened was probably when her son was on set and he came up to me and he said, 'Why did you kill my mom?'" recalled Roth, 35. "I said, 'I didn't know it would be your mom when I did it,' And he was like, 'That makes sense.' That was it. He walked away after that."

The three Divergent films came out in 2014, 2015 and 2016. Roth remembers Winslet, 48, as being "so friendly" during the making of the movies.

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"You can always tell something about a person by the way they treat the assistants on set, and she was such a joy to deal with for all of them," she said. "I've been a fan of hers for a long time and she was so cool — just really aggressively cool."

Winslet was pregnant with her third child, son Bear, when she filmed Divergent. She revealed back in 2013 that she took the part in the YA franchise partially as a way to impress her kids. She's also mom to daughter Mia, 23.

"My daughter is going to be 13, and my son is almost 10, and they're getting to that age where this is the type of literature they're going to be reading very soon," she told MTV News at the time.

"In fact, my daughter, two days ago, came home from school and went, 'Mom! You're never going to believe it. Rufus came up to me at school and said, 'Is your mom really in Divergent? Is there going to be a premiere? Can you get me a ticket?' "

Winslet joked, "My daughter suddenly [had a] newfound respect. 'My mom is actually really cool.' I'm just going to go with that: I did it because I wanted my kids to think I was cool."

Since wrapping up the Divergent series, Roth has written several other books, including Poster Girl, now in paperback, and, coming in May, When Among Crows. She says, though, her Divergent characters continue to live on in her imagination.

"I'll be like, 'What if that person had lived? What if a completely different plot point had happened or a different perspective?' But I don't think about it that often," says Roth.

"I've got a lot of characters living in my head now, but every so often. I think they were the strongest point of the series, the characters, so they're the part that lives on the most for me."

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