In attempting to define the word on SNL, she cited an incident where US businesswoman Martha Stewart had mistakenly claimed a journalist who covered her legal proceedings was dead.
“Martha gets mad about an old magazine article and she says that she’s glad the journalist who wrote it is dead – that is brat,” she said.
“And then last Friday, when that exact journalist responded and said, ‘Hey, ‘I’m alive…’ – that is extremely brat.”
Charli, who was also a musical guest on the show, went on to say: “Honestly though, anyone can be brat.”
“Keeping it real is very brat, it is all about being vulnerable, so truly, this is a dream come true,” she said.
“I am so excited to be here, and I’m not used to being out this early on a Saturday night but for you guys, it’s worth it.”
Charli has previously defined brat as a girl who “has a breakdown, but kind of like parties through it”, who is honest, blunt, “a little bit volatile”.
She told the BBC’s Sidetracked podcast that someone brat might have “a pack of cigs, a Bic lighter and a strappy white top with no bra”.
Creating an aesthetic has been something popularised on TikTok, with Charli’s brat girl summer seen as a rejection of other trends such as the “clean girl” who looks feminine and well kept.
Brat was crowned Collins Dictionary word of the year earlier this month, with lexicographers defining it as someone with a “confident, independent and hedonistic attitude”.