Hailey Bieber ''loves hats'' after learning the importance of protecting herself from the sun.

The 23-year-old model admitted she ''never used to wear a hat in the sun'', but since learning some important information about the way the sun's UV rays impact the collagen in skin - which helps to keep skin looking youthful and plump - she's become an avid wearer of headgear.

Posting on her Instagram story, she wrote: ''I never used to wear a hat in the sun but since learning we lose 1% of our collagen a year after the age of 23 suddenly, I love hats?? (sic)''

The message comes after Hailey revealed last month she ''doesn't always'' wear sunscreen to protect herself from the sun, but will occasionally apply EltaMD UV Clear Broad-Spectrum SPF 46.

At the time, she told her followers: ''Can't lie I don't always wear SPF but when I do this is the only one that doesn't make my skin breakout. I'm super sensitive to sunblock.''

Meanwhile, the blonde beauty - who is married to Justin Bieber - recently hit out at critics who insinuate she has had cosmetic surgery to alter her face shape.

She commented on a photo of herself which has since been deleted: ''Stop using pics that are edited by makeup artists! This photo on the right is NOT what I look like ... I've never touched my face so if you're gonna sit around and compare me at 13, and then me at 23, at least use a natural photo that wasn't edited so crazy. (sic)''

Hailey and Justin have even sent a cease and desist letter to Dr. Daniel Barrett, after the plastic surgeon made a TikTok video in which he suggested the model had gone under the knife to alter her appearance.

A section of the cease and desist letter reads: ''These flagrant and conscious infringements of our Clients' rights constitute a number of violations including, without limitation: misappropriation of name, likeness, image and persona for commercial purposes, misrepresentation, defamation, slander, false light, violation of rights of publicity, copyright infringement, trademark and service mark infringement, unfair competition, dilution, and interference with our Clients' contractual obligations to third parties.''