Mario Testino is the ''true light'' in Gigi Hadid's life.

The 21-year-old model has taken to social media to post a heartfelt message to the 62-year-old fashion photographer to commemorate his birthday on Sunday (30.10.16), which saw Gigi reveal it has been an ''honour'' to work with the fashion mogul throughout her career.

Alongside a picture of the pair whilst on a shoot, which has been edited in black and white and shared on the blonde beauty's Instagram account, she wrote: ''Happy Birthday to a true light in my life @mariotestino - it will forever be an honor to be in front of your lens & to learn from you; most of all, I'm so grateful to call you my friend. Thank you for the adventures and the laughs. Wishing you a beautiful day today and many many more. All my love. (sic).''

However, Gigi isn't the only style icon to pay tribute to Mario on his birthday, as fellow models Naomi Campbell and Karlie Kloss have also taken to social media to send birthday wishes to the Peruvian star.

Alongside a picture of Karlie and Mario on the red carpet, the 24-year-old catwalk icon wrote: ''Happy birthday@mariotestino! It is a true privilege to work with you, and even more so to call you a dear friend. Thank you for the countless laughs we've shared together. Here's to many more years! (sic).''

Whilst, Naomi Campbell - who has boasted a career spanning over 30 years at the helm of the fashion industry - gushed about the star and their ''30 years of solid friendship'', a bond which she hopes will continue for many more years to come.

She said: ''#happybirthday my darling @mariotestino #30 years of solid friendship and it only gets better !!! I wish for you most amazing year and may you do all the things you ever dreamed of doing !!! Your surrounded by Angels enjoy this beautiful day and Know you make others look beautiful and you are too inside out #family #love#loyal #unconditionalove (sic).''