In the new movie 'The Butler,' Mariah Carey plays the sharecropper mother of an African-American man who would later serve as the White House butler for more than three decades. But while Mariah's character is raped in the film, that wasn't even the scene that disturbed her most.

That honor went to a recreation of the 1960 sit-in at a North Carolina Woolworth's lunch counter, where a black college student asked to be served and a white woman spat in his face -- something Mariah says once happened to her.

The bi-racial Carey (her mother is white and her father is African-American/Venezuelan) grew up in suburban Long Island, but she was still sometimes the victim of racism. And as she said during a press conference on Monday that was also attended by 'Butler' star Oprah Winfrey and other cast members, the spitting incident in the movie struck a nerve.

"That actually happened to me [on a school bus]," Mariah, 44, said. "I know people would be in shock and not really want to believe or accept that, but it did ... That right there, that was almost the deepest thing to me in the movie because I know what she went through."

"Where somebody spit on you?" Winfrey asked.

"Yeah," Carey replied. "In the face and in the same way."

These days, she's considered one of the most beautiful and glamorous women in showbiz -- but insecurities from childhood mean that even now, she doesn't always feel that way.

"Growing up and being half-black, half-white, I felt weird; I didn’t look like anybody. My friends were all different from me,” Mariah told StyleList back in 2009. “No one knew how to fix my hair. My facial features stood out. And I know we [mixed people] all say that. But even though I’ve grown since, some of those things still remain with me.”