If you're black or Asian then you might be familiar with other black and Asian people making comments on how light-skinned or dark-skinned you are.
If you're not, you might have heard these comments being made at school or elsewhere.
Colourism is a form of racism which is usually seen when people are negative about people who have a darker skin tone. It also includes people that treat others with a lighter-skin tone better.
It is something that I remember seeing in school and is something that still happens in society today.
One place where you might see it is the entertainment industry. A lot of people think that light-skinned people in the industry are more likely to be successful in comparison to darker-skinned people.
There was a lot of backlash recently around reports that actor Will Smith was cast to play the father of Venus and Serena Williams in a brand new film.
The problem? People were upset that Richard Williams is dark-skinned and would be played by Will Smith, who has lighter skin. They thought the role should have gone to a dark-skinned actor because people thought it was unfair to let Will play the role.
When I was in school a lot of my friends were black.
Being a dark-skinned boy myself, we often made comments based on each other's skin tones.
As we've grown up, we've stopped because we have realised how comments like that can be quite harmful even if they are just said within our friendship groups.
That's because it can make people feel upset about themselves just because of the shade of their skin.
For me personally, I've realised how important it is to know that whether you are dark-skinned like me or have lighter skin tone, it is just skin tone and does not define who you are as a person.