A new book called “Frenemies in the Family” aims to shed light on the real relationships of some famous personalities.

Kathleen Krull, the author of the book, recently spoke with Parade about the focus of the children’s book. Princes William and Harry, Serena and Venus Williams, and Stephen Colbert and his siblings’ relationship are all discussed in the pages of her creation.

“Frenemies in the Family” also combines historic figures with contemporary ones to make it a more compelling read. “I think Serena and Venus Williams are absolutely fascinating, so are the Princes William and Harry and it was so interesting learning about Stephen Colbert – who knew he had 10 older siblings?” Krull said.

Princes William and Harry grew up together, and they got even closer after the death of their mom, Princess Diana. Last year, the Kensington Palace released a seven-minute video featuring the brothers and Kate Middleton having a conversation.

In the clip, Prince Harry tells his brother and sister-in-law that he didn’t want to talk about Princess Diana for fear that bringing back the past would just hurt him. “I do think it’s incredible how strong and how you’ve been able to cope really, and I put that down to your really early years and your childhood experience. But also the relationship William and Harry have… you’re amazingly close,” Middleton said.

Prince William responded, “We have been brought closer together because of the circumstances… we are uniquely bonded because of what we’ve been through. But even Harry and I over the years have not talked about our mother.”

Princess Diana and Prince Charles’ sons are also very playful towards each other. After Prince Harry announced his engagement to Meghan Markle, Prince William released a statement and said that he hopes the engagement means his brother would finally stop eating his food.

“For me personally, I hope it means he stays out of my fridge and will stop scrounging my food, which he’s done for the last few years!” he said (via ABC News).

“We’re very excited, delighted for them both. We’re wishing them all the happiness in this very exciting time,” he added.