CLICK ON PHOTOS FOR FULL GALLERY
"This is me at 15, winning the "Look of the Year modeling award in Germany"...HOW you might ask? I really don’t know…" she quipped in the caption alongside the photo of herself rocking a typical 1980s voluminous updo, beaming as she poses in a floral dress and black feather boa.
"Maybe that year baby face with too much make up and crooked teeth was in style? Maybe they were playing a cruel joke on me??" she continued. However, it seems that the National Treasure star had an inspirational message to teenagers around the world.
"Whoever picked me… thanks for the Vespa I won and the life that opened up to me!!!!" she wrote. "All you awkward looking girls out there!!!! SOMEONE thinks you're pretty!!!"
Diane often channels old Hollywood on the red carpet
Fans immediately took to social media to praise Diane for her inspirational message, while others noted that even Diane's 'awkward' phase sees her natural beauty shining through.
It comes as no surprise that the actress kicked off her career by winning a beauty pageant. Jaws drop whenever she steps out on the red carpet, often channelling old Hollywood by wearing her shining blonde locks in retro curls and completing the look with a slick of statement lipstick.
The Troy star is also currently the face of Chanel beauty. Her flawless complexion has seen her fronting the latest campaign for the brand's new Hydra Beauty Micro Serum. She recently shared a selfie while having her hair and make-up done to film the latest instalment of the campaign, in Los Angeles.