• Colourism she said is prejudice against people who have a darker skin tone or the preferential treatment of those who are of the same race but lighter-skinned.
• The actor said she was once told at an audition that she was too dark for television.
Award-winning actress Lupita Nyong’o has opened up on her battle with low self-esteem and colourism while growing up.
Lupita was raised in Kenya, before moving to the United States.
Growing up, she was a victim of colourism and wished to have a different skin tone.
The Oscar-winning actor told BBC Newsnight on Tuesday that colourism is the daughter of racism in a world that rewards lighter skin over darker skin.
Colourism, she said, is prejudice against people who have a darker skin tone or the preferential treatment of those who are of the same race but lighter-skinned.
"I grew up feeling uncomfortable with my skin colour because I felt like the world around me awarded lighter skin," she narrated.
Her younger sister, whose skin was lighter, was called "beautiful" and "pretty".
"Self-consciously that translates into: 'I'm not worthy'," she said.
Lupita, who won a best-supporting actress Oscar for 12 Years a Slave, said colourism was very much linked to racism despite the fact she experienced it in a predominantly black society like Kenya.
"We still ascribe to these notions of Eurocentric standards of beauty, that then affect how we see ourselves among ourselves," she said.
The actor said she was once told at an audition that she was too dark for television.
But Nyong'o said the relationship to her skin had been separate to the relationship to her race.
"Race is a very social construct, one that I didn't have to ascribe to daily growing up," she said.
"As much as I was experiencing colourism in Kenya, I wasn't aware that I belonged to a race called black."
That changed when she moved to the US because suddenly the term black was being ascribed to her which meant certain things that she was not accustomed to.
She spoke ahead of the release of her children's book, Sulwe, on October 15.
'Sulwe', meaning Star is about colourism, self-esteem, and learning that true beauty comes from within.
In the debut picture book, the actress creates a heartwarming story to inspire children to see their own unique beauty.
"Sulwe holds up a mirror for dark-skinned children especially, to see themselves reflected immediately, and it is a window for all the others to cherish peering into," she wrote on Twitter on Tuesday.
In a series of tweets, Lupita said as a child she had all windows into the lives of people who looked nothing like her.
She had chances to look into their worlds, but she didn't have any mirrors.
While windows she said help us develop empathy and an understanding of the wider world, mirrors help us develop our sense of self, and our understanding of our own world.
She said Colourism, society's preference for lighter skin, is alive and well.
"It's not just a prejudice reserved for places with a largely white population. Throughout the world, even in Kenya, even today, there is a popular sentiment that lighter is brighter," she said.
The book is a dream come true she imagined having a book with more dark skin in a beautiful light.
Asked whether the film's success had changed the casting experience for black actors, Nyong'o told Newsnight: "I think time will tell whether this has been that pivotal shift. It definitely feels that way."