Cindy Crawford’s son Presley Gerber just earned the title of “best big bro ever” from sister Kaia Gerber. That’s what the top model wrote on Instagram stories when her brother decided to get inked in honor of Kaia. Gerber went to celeb tattoo artist Jon Boy (a favorite of Hailey Baldwin, Kendall Jenner, and Bella Hadid) at Bang Bang Tattoos in New York City on Thursday and got his sister’s name “Kaia” tattooed on his left arm. That’s just how close the model siblings are — it’s even more permanent than their newest campaign together for Calvin Klein.

Under Kaia’s name, Presley got the roman numerals signifying the number 23. It’s not quite clear yet what that number represents, but Instagrammers are taking guesses that it might be a combination of their birthdays. “2 July (Presley’s Birthday) 3= 3 September (Kaia’s Birthday),” one wrote. Presley’s girlfriend Charlotte D’Alessio came along to the tattoo shop with the siblings for moral support.
But what did Presley and Kaia’s parents think of their 18-year-old son’s new ink? They both wrote in with approval on Presley’s instagram. “RG + JG APPROVED!” Dad Rande Gerger wrote, while Cindy Crawford summed it all up, saying “Cool.” C’mon, Cindy, this deserves an emoji at least.