Kaia and Presley Gerber star in Calvin Klein's latest advert together.

The sister and brother come from modelling royalty as their mother is supermodel Cindy Crawford, but the pair are making their own names in the fashion business and they can now be seen showing off their playful sibling rivalry by taking part in a series of games for the newest Calvin Klein #MyFamily advert.

Following in the footsteps of the Kardashian/Jenner clan, Solange Knowles, Paris Jackson and Millie Bobby Brown who have all starred in previous Calvin Klein campaigns this year, Kaia, 16, and Presley, 18, are dressed head-to-toe in western inspired denim and play fight, arm wrestle, and take it in turns to catch each other in a bid to win the top spot of superior sibling.

However, it appears there is no real life rivalry between the two - whose dad is businessman Rande Gerber - as Presley even got a tattoo dedicated to his little sister in February.

He visited Bang Bang Tattoos in New York City during Fashion Week in order to get his 16-year-old sibling's name inked on his arm, along with the number 23 in Roman numerals.

And the tattoo proved to be popular with the close-knit family, with Kaia posting the picture on her Instagram account with the caption, '''presleygerber best big bro ever'', along with three broken heart emojis, and father Rande commented ''RG + JG APPROVED!'', while Cindy simply added, ''Cool.''