Hamilton wore a helmet featuring the Pride Progress Flag, a redesigned and more inclusive version of the traditional rainbow flag, and emblazoned with the words "We Stand Together."
The flag features additional black and brown stripes to highlight the oppression of people of color, as well as pink and blue stripes for the trans flag and a purple circle on a yellow background, which is the intersex flag.
Although the Pride Progress Flag was initially designed by American artist Daniel Quasar in 2018, it was British intersex activist and columnist Valentino Vecchietti who finalized the version seen on Hamilton's helmet, which includes the intersex flag.
"It means everything," Vecchietti told CNN. "I can't express what an amazing, massive, massive thing Lewis Hamilton has done. And I feel emotional talking about it, because we are so hidden and stigmatized as a population."
According to the United Nations Free and Equal campaign, up to 1.7% of the global population is intersex, or does not have sex characteristics that conform to "typical binary notions of male and female."
Highlighting the erasure of intersex people both within the LGBT+ movement and in society as a whole, Vecchietti said Hamilton's gesture would also raise awareness of the vilification of intersex athletes like Caster Semenya and Dutee Chand in sport.
"We have to remember that young kids with intersex variations growing up in school see all this media," she said. "As an intersex person myself, at school, I grew up with so much stigma and shame and feeling I had to keep it hidden ... Lewis Hamilton has done something amazing. He's given me a platform to begin these conversations on a much larger scale."
Vecchietti, the founder of Intersex Equality Rights UK, designed the flag with the support of Stonewall and the LGBT Consortium, and her design quickly went viral after it was shared on social media in May.
Hamilton's decision to wear the flag on his helmet also comes at the end of Trans Awareness Week, while Saturday marks the International Transgender Day of Remembrance.
Racing Pride, which aims to promote LGBTQ+ inclusion in motorsport, also praised Hamilton, calling the helmet "a magnificent and powerful gesture of solidarity."