Kim and Pete both rely on *this* blonde-freshening treatment

How does the old saying go again? Couples who keep their blonde fresh together stay together? Ah, perhaps we're paraphrasing, but hey it works! It's a sentiment that rings true for power couple Kim Kardashian and Pete Davidson (AKA 'Kete' to anyone in the know).

In fact, not only did the pair go platinum within weeks of each other, but it's alleged that they also share a favourite treatment in common for keeping said icy shade bright, fresh and healthy.

The treatment? K18's Leave-In Molecular Repair Hair Mask ($94 at Sephora), an Olaplex alternative designed to combat the fun hair concerns that come with going bright blonde; think dryness, damage, split ends and brittleness. Featuring the brand's patented K18 peptide, it dives deep into the hair's core structure to 'reconnect' broken bonds and up hair health levels.

So how do we know the platinum pair rely on said fancy formula? Kardashian confessed her affinity for it in a chat with Allure, noting that she uses "a lot of K18", while the brand itself has mentioned that Davidson is a fan of the product.

'Kete' arent' the only fans in the family, though. Khloé Kardashian raves about the stuff too: "My hair was very damaged and my stylist recommended this leave-in repair mask. It literally brought my hair back to life. Obsessed!", she shared via Twitter. So that's how she keeps her blonde looking so luscious!

As for how to use it if you're keen on joining the club, here's the gist: hop in the shower and shampoo as usual but don't condition; once you're out, towel-dry your hair and work a pump (or two) of the treatment through strands. Leave it for four or so minutes (to activate), then style as usual - easy!

We knew the stuff was good but endorsements from two Kardashian sisters (and Pete, of course) sends its rep through the roof. Fitting that it's called K18, huh?!

Main image credit: Getty Images

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