The hotel heiress became known for saying the phrase in the early 2000s, when describing things that she liked. But in a video interview with Vogue, Paris revealed it was actually her sibling that coined the saying.
"I started making shirts that said, 'That's hot,' and on the back they said, 'You're not.' It was cute," she said. " 'That's hot' was something that my sister always used to say, but I trademarked it and I own it. Sorry, Nicky."
As well as always saying "That's hot," Paris was also known for always wearing Juicy Couture velour tracksuits - and appeared to have one in every colour. She was first sent one of the two-pieces by her friend and publicist Lara Shriftman, and said that as soon as she put it on, she was "obsessed."
"I said, 'Please send me more. I want the full collection. Every single colour,' " she smiled. "I just fell in love with the brand and it basically became my uniform. I have an entire closet that's only Juicy Couture. It's somewhere I go every single day and just put on my Juice."
"I was not only wearing them to the airport or just to chill in my house in. I was going out at night in them and I was rocking them with everything. So I think that they loved that I was kind of like the face of the brand."