The singer and TV star spoke to her husband Marvin Humes about her experiences for the new Channel 4 documentary The Talk.
Sharing a clip of their conversation on Instagram, she said: “My legs were red because I had tried to scrub my skin off. And I’m not upset for me, I’m just upset because I think my little girl is the same age. I just don’t know how I would handle that.”
She wrote: “Opening up about racism and my challenges was overwhelming as it reminded me that we still live in a world where racism is normalised and accepted.
“I don’t want my children growing up in a world where they think that their heritage and skin colour could be judged negatively. That’s why I was so emotional, not for me, but for every child or person who has been made to feel like they were not enough because of their skin colour.
“So I allowed myself to open up and be vulnerable about this topic publicly to help support others through shared experience and also educate people on the lasting impact racism and discrimination can have on people.”
The documentary will detail the conversation many black parents have with their children to explain that their skin colour will mark them out for prejudice and challenges not faced by white people.
The film will feature leading black public figures sharing memories of the talks they have given or received, contextualised by family archives or an event that triggered the talk, such as a prominent death in police custody.
It will be part of a series of programmes exploring different aspects of the black experience in modern Britain.
It will air on Channel 4 on Tuesday.