In their latest Calvin Klein campaign, Kaia and Presley Gerber gave the world a brief glimpse into growing up in their household.

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Joining the likes of the Kardashian-Jenners, Solange Knowles, Paris Jackson and Millie Bobby Brown, the supermodel offspring put on their best double-denim for the Raf Simons-run fashion house.

As the daughter and son of OG model Cindy Crawford and entrepreneur Rande Gerber, the pair are notoriously close.

Presley, who is 18 years-old, already has a tattoo of his 16 year-old sister's name on his arm, proving the pair are thicker than thieves.

However, what is sibling love without a dash of rivalry, eh? No siblings are impervious to that, right?

Indeed, and, thankfully, we have new video footage to prove it.

Alongside their stunning still shots, Kaia shared a video of the pair play fighting on set, including the classic wet willy move, and 'trust' exercises.

By the looks of things, younger sister Kaia may be more accomplished at all playground foolery, winning at both an arm wrestle, as well as slapsies.

The siblings are two of the most sought-after models in the industry right now, not least due to their extremely engaged Instagram followers. Thankfully, despite their successes, the pair are still able to act like big kids.