In July 2019, the six-year-old was spotted holding an awesome unicorn purse while the Duke of Cambridge competed in a charity polo day, and she also had a unicorn key chain attached to her backpack when she arrived for her first day of school at Thomas's Battersea that September.
So when William hosted a special Q&A session on Instagram on Oct. 14, he couldn't resist bringing Charlotte up when a fan asked a question that seemed sort of out of left field.
The day before, the duke put out a call-out for questions on the account he and Duchess Kate share, saying he was taking questions about the Earthshot Prize, his groundbreaking initiative that encourages entrepreneurs to come up with solutions to climate change.
"Are unicorns real?" one person asked.
When the question came up on screen, the dad of three started giggling.
"Well, I think if you talked to my daughter, she'd say they were real," he quipped, before adding, "Obviously, it's a trade secret, so I can't possibly comment."
William hosted the rare session to raise awareness about the Earthshot Prize, which hands out its first five awards at a ceremony at London's Alexandra Palace on Oct. 17. It will feature performances from the likes of Coldplay, Ed Sheeran and Shawn Mendes and presenters will include Emma Thompson, Emma Watson, Mo Farah and more.
Five of 15 finalists will be named the first-ever winners at the event. Their evidence-based solutions will be recognized for making the most progress towards the program's highlighted goals.
William launched the Earthshot Prize in December 2019. It is described as "the most prestigious environmental project in history" and wants evidence-based solutions to help fix the emergencies facing the natural world.
Following the first prize in London in 2021, Earthshot Prizes will be handed out to five Earthshots every year until 2030. The hope is the winners' work will provide at least 50 solutions to the world’s greatest problems by the end of the decade.
In his Q&A session, William said he was inspired to create the prize because he believes climate change and the challenges our planet faces are solvable and that he's optimistic the prize can help.
William and Kate are clearly passing their passion for the planet on to their children. Earlier this week, the duke revealed Prince George was very aware of the climate crisis, while Charlotte and Prince Louis are still a bit too young. George is already turning into a little environmentalist, by the sounds of things.
"George, at school recently, has been doing litter picking, and I didn't realize, but talking to him the other day, he was already showing that he was getting a bit confused," William told the BBC on Oct. 13.
"[He was] a bit sort of annoyed by the fact they went out litter picking one day, and then the very next day, they did the same route, same time and pretty much all the same litter they picked up was back again.
"And I think that for him, he was trying to understand how and where it all came from. He couldn't understand. He's like, 'Well, we cleaned this. Why has it not gone away?'"
The duke previously said he'd also been inspired by create the Earthshot Prize because he wanted to be able to look his children in the eye and tell them he did all he could to solve climate change.
"I think it is slowly dawning on them that these things matter," he told BBC this week. "But I think when you're that young, you just want to have fun and enjoy it. I feel bad; I don't want to give them the burden of that worry."
William and Kate are doing everything possible to ensure their kids have strong connections to the great outdoors and our planet. They encourage the children to spend as much time as possible outdoors, and have also instilled a love of nature through Sir David Attenborough's documentaries and TV programs.
Last year, the Cambridge kids were part of an adorable Instagram video in which they each asked the legendary natural historian about animals, which you can watch below.
You can also watch the Earthshot Prize live on Discovery's Facebook page and Discovery+ on Oct. 17!