Image copyright Getty Images Image caption Reports that Will Smith is tipped to play Richard Williams have sparked accusations of colourism

An upcoming biopic about the father of Serena and Venus Williams has faced criticism amid reports that Will Smith will play the lead role.

Richard Williams, 77, coached his daughters to become two of the world's greatest tennis players, despite having no previous experience of the game.

But Smith's reported casting in the film has angered critics, who say he is too light-skinned for the part.

The actor has not yet commented on the reported casting or the criticism.

Colourism is a form of discrimination against dark-skinned people in favour of those with lighter skin from the same race.

Image copyright Getty Images Image caption Richard Williams coached his daughters to the top of the game

It can lead to a lack of representation in film, TV and fashion, particularly in Hollywood and Bollywood, as well as discrimination at work or on dating sites, and even to serious health problems from skin bleaching creams.

Media playback is unsupported on your device Media caption Colourism: "There's not just one way of being beautiful"

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What have people been saying?

Smith's casting in the film has not been confirmed. However, after a report from Deadline News claimed that the 50-year-old actor was "poised to play" Mr Williams, many people expressed their anger on social media.

The criticism stems from the fact that Smith is significantly lighter than Mr Williams.

US-based sports writer Clarence Hill Jr tweeted that "colourism matters", and said that Smith wasn't the right choice.

This sentiment was echoed by many others, who felt that giving the part to a dark-skinned actor would "make more sense".

Skip Twitter post by @so_rudez Why is he always cast in roles portraying dark skin men like there aren’t tons of black actors that would make more sense for the role? https://t.co/1VcZyCmwTK — Deepocket Chopra (@so_rudez) March 5, 2019 Report

People also suggested other actors who could take on the role - including Idris Elba, and Oscar-winner Mahershala Ali.

"Colourism is constantly subconsciously fed to us and we just eat it up," one user added.

Skip Twitter post by @reyemoon I love Will Smith more than anyone but why not cast Mahershala Ali or somebody darker skinned like the man being portrayed actually is ☹️ #DarkSkinMatters — Re Moon (@reyemoon) March 5, 2019 Report

Skip Twitter post by @TrillaKilla007 Why couldn’t they get someone like Idris Alba to play Venus’ and Serena’s dad in the upcoming movie?



Why are they whitewashing the dad with Will Smith. 🌚 colourism is constantly subconsciously fed to us and we just eat it up... — Uncomplet_d (@TrillaKilla007) March 5, 2019 Report

However, one person did point out that Ali and Elba might be too in-demand to be able to take on another film.

Skip Twitter post by @nw3 This Will Smith colorism scandal is also silly because Mahershala Ali and Idris Elba are far more in demand. They’re trying to get cast as James Bond, not Serena’s dad. — Nick Walker (@nw3) March 5, 2019 Report

And another said the casting made sense as, although he has lighter skin, Smith is still a "prominent black actor" playing a "prominent black figure in the sports industry".

Skip Twitter post by @BeLikeLika As if this is Brad Pitt proposing he should play the role of Richard Williams in black face. Will Smith is a prominent black actor executing the role of a prominent black figure in the sports industry. Why is colourism even a concern here??? — Transfinancial (@BeLikeLika) March 5, 2019 Report

This isn't the first time a Hollywood film has become embroiled in a colourism row.

The casting of Zoe Saldana, a light-skinned actor of Puerto Rican and Dominican descent, as the African-American civil rights activist and musician Nina Simone in 2016 sparked similar criticism.