"Growing up I always thought maybe I was a little bi-curious. I only ever dated straight people but growing up I did have crushes on girls."
Maria admitted that she "buried" the part of herself that felt attraction to women, adding that it felt "easier" to just date men.
But just before filming began for the show, the 28-year-old met a woman at a party who inspired her to embrace her bisexuality.
"We ended up hooking up and it just felt natural. It just feels bl—dy good to say it," Maria continued.
"I don't want to carry any shame or stigma about it and … I just want to break out of that."
Taking to Instagram after the episode aired, Maria expanded on the moment she came out to David – and the rest of Australia.
"Before the show, I had only come out to a handful of people," she penned alongside three photos of her in rainbow makeup.
"My brother took my call at midnight last night and talked it over with me - and I realised the reason I've been so f--king scared to do this is exactly why I need to."
Maria confessed that only seeing heterosexual people and relationships in the media and society around her had caused feelings of confusion and shame.
"A lack of bisexual visibility for most of my life has meant that the experience was confusing and there were parallels to other experiences I had with social identity," she explained.
"Fear of falling in between the cracks, never fully finding a place in myself. But when I spoke to @domthattil, he reminded me about why we call it #PRIDE."
She concluded her message by reminding the world that her sexuality is "no longer a secret to protect but a part of me to celebrate".
The I'm A Celeb… fan favourite was flooded with supportive messages from her fellow contestants, as well as other Australian stars.
Dylan Lewis wrote "Respekt sista. X❤️", Davina Rankin added "So so so proud of you ❤️" and Beau Ryan chimed in "Proud of you❤️."
Dannii Minogue also commented, writing: "🌈 loving these words and pictures. You will fly the flag for so many people now."
WATCH: I'm A Celeb's Maria Thattil and Joey Essex discuss their plans for kids (Story continues after video)
Australia's first bisexual Bachelorette Brooke Blurton left a string of pride flag emojis in the comments section, to which Maria replied: "I love you. You have helped me more than you know."
Maria's on-screen admission follows a recent trend of LGBTQ+ representation in Australian reality TV, with networks slowly improving the diversity in casting.
This year marked the first time a Bachelorette dated contestants of multiple genders, and Married At First Sight has cast multiple queer contestants.
This article originally appeared on our sister site, Now To Love.