Kaia Gerber accompanies 'best big bro ever' Presley while he gets tattoo of her name: Pic

No sibling rivalry here.

Presley Gerber paid tribute to his younger sister Kaia on Thursday in a very permanent fashion -- with a tattoo of her name on his left arm. The 18-year-old opted for the fashion model's name in lowercase script with the roman numeral for "23" inked just below.

Kaia, 16, was present for the inscription at New York City's Bang Bang Tattoos, as was Presley's girlfriend Charlotte D’Alessio, 19. Presley, also a fashion model, took to Instagram to show off his new ink, while his sister posted the same photo on her Instagram story alongside the caption, "Best big bro ever."

Famed tattoo artist JonBoy, who has inked the who's who of Hollywood from Kendall Jenner to Bella Hadid, did the detailed work and posted a shot of himself -- in his trademark Gucci apron -- posing with the trio.

The devoted brother-and-sister pair's famous parents -- supermodel Cindy Crawford and husband Rande Gerber -- also chimed in with their approval. "RG + JG APPROVED!" penned their proud dad in the comments, while Crawford simply wrote, "Cool."

Despite working in the same industry, and a competitive one at that, the model siblings are as close as any brother and sister can be. All eyes were on the hardworking duo at the CFDA/Vogue Fashion Fund Show last fall, while they also recently starred in the Calvin Klein Jeans ad campaign.