EXCLUSIVE: Tess Holliday on Why She Called Out Chloe Grace Moretz for 'Red Shoes' Body Shaming Controversy

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Tess Holliday says she was horrified when she saw a controversial poster for the upcoming animated film, Red Shoes & the 7 Dwarfs, which compelled her to tweet about it.

ET spoke to the 31-year-old plus-size model on Thursday, and she talked about tagging the movie's star, actress Chloe Grace Moretz, in a tweet slamming an advertisement for the film. A billboard for the movie in Cannes, France, shows two women -- one tall and thin, the other shorter and heavier -- and the words, "What if Snow White was no longer beautiful and the 7 dwarfs not so short?" Moretz addressed the issue on Wednesday and tweeted that she too was "angry and appalled" by the film's marketing.

WATCH: Chloe Grace Moretz Responds to 'Red Shoes' Body Shaming Marketing Backlash -- I'm 'Appalled' and 'Angry'

"My first reaction when I saw the ad campaign was horror, I think," Holliday tells ET. "I had to look at it to see if it was real, because I couldn't wrap my head around if that was a real movie poster in 2017."

"The fact that they put on the poster, or it was implied that Snow White wasn't beautiful because she was plus size, part of why that bothered me was the obvious," she continues. "This movie, you're catering it to young girls -- young children, even -- you know, big kids like me who love Disney or just that genre. You're telling them that it's not OK to look the way they do or be plus size at all, and more than likely, these children have parents or someone in their lives that look like me. They might be plus size themselves, and so it's just sending a message that they're not OK the way that they are or someone in there life isn't, which is obviously really damaging, which is why I was so confused on how it came about to begin with."

Moretz tweeted that the marketing wasn't approved by her or her team. "Please know I have let the producers of the film know," the actress wrote. "I lent my voice to a beautiful script that I hope you will all see in its entirety ... I am sorry for the offense that was beyond my creative control."

Holliday says she's pleased that 20-year-old Moretz addressed the concerns.

"The only reason I tagged Chloe in the tweet was because I was just a little shocked that someone who's been so vocal about feminist issues and things that this movie says is encompassing, I kind of was like, I feel like she doesn't know this is happening," Holliday explains. "I wasn't attacking her at all, it was more like I was saying, 'Hey, you're in this movie and why was this OK to say?'"

"I think it's wonderful that Chloe made the producers aware," she adds. "I'm just really glad that they're handling it and they realize that it wasn't OK. I just don't know why it took some fat girl on Twitter."

Holliday's upcoming book, titled The Not So Subtle Art of Being a Fat Girl: Loving the Skin You're In, is available on Aug. 24.

NEWS: Everything You Need to Know About Tess Holliday, the Size 22 Supermodel Who Is Changing the World

Last May, Holliday talked to ET about fighting back against her haters after she posted a nearly nude pregnancy photo of herself.

"I really don't care if people think I'm unhealthy," Holliday said. "I feel like it's so clear. Our bodies are our business, and it's OK to be who you want to be, and I think most people get that."

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