On Tuesday, when the bizarre news broke that white British actor Joseph Fiennes was cast to play black American superstar Michael Jackson in a “9/11 road trip comedy”, it seemed as if Hollywood had learned nothing from the #OscarsSoWhite uproar which has arisen in the wake of the Motion Picture Academy nominating only white actors for Oscars this year.

The internet has been ablaze questioning the wisdom of Fiennes going forth to play the King of Pop in Elizabeth, Michael and Marlon, the tale of an alleged road trip taken by Jackson, Elizabeth Taylor and Marlon Brando after the attacks on the World Trade Center in 2001. But according to the British production cable channel Sky Arts, the casting is a done deal, as the half-hour comedy was shot last year. Though a story surfaced this week quoting Fiennes as if he just received the script “the other day”, the project is already in post-production.

The show “will be coming to Sky Arts in 2016, the exact transmission date is still to be confirmed”, Dominic Collett, a publicist for Sky Arts, confirmed.

“This is a one-off, half-hour comedy for Sky Arts,” she wrote, describing it as “a light-hearted look at a reportedly true event” in “part of a series of comedies about unlikely stories from arts and cultural history.”

It’s hard to ascertain for sure, but the road trip is such an unlikely story that the truthfulness of the “reportedly true event” has been debunked by at least one of Taylor’s assistants in Vanity Fair.

Regardless, one would be allowed to question why the makers chose to cast the white star of Shakespeare in Love as Michael Jackson. Asked about the thinking behind this, Collett wrote: “Sky Arts gives producers the creative freedom to cast roles as they wish, within the diversity framework which we have set.”

But “diversity”, a word Selma director Ava DuVernay wants people to stop using, is a blanket term. It’s easier to talk about than “racism”, “structural racism” or “anti-blackness”. Having a white actor play such an important African American legend remains problematic.

Blackface is still blackface even when portraying a light-skinned African American.

Though he could be read cosmetically as racially ambiguous at the end of his life, Michael Jackson was black. He was born black to Joe and Katherine Jackson in Gary, Indiana (which is now 85% black). He had four black brothers in the Jackson Five. And he was so Motown, he made Diana Ross the godmother of his son. Can a white actor capture this blackness?

“For just about anybody born in black America after 1958 – and this includes kids I’m hearing about who are as young as nine years old right now – Michael came to own a good chunk of our best childhood and adolescent memories,” Greg Tate wrote in the Village Voice in 2009 just days after Jackson died. A white actor can’t possibly capture the impact he had on so many of us black kids back then, and can’t have lived a life that would help him understand how Jackson performed race as he did.

And whatever he looked like in the end, Jackson got there as a man who was so black, whose blackness was such a part of him, he made They Don’t Care About Us – a video which Jackson sings about being “the victim of police brutality” who feels he has become “invisible because you ignore me”.

“The absolute irony of all the jokes and speculation about Michael trying to turn into a European woman,” Tate wrote, “is that after James Brown, his music (and his dancing) represent the epitome – one of the mightiest peaks – of what we call Black Music.”

In 2014, when only white people were cast to play Egyptians in the film Exodus, the defense I most often heard is that acting is acting and actors can play anyone. But black actors have struggled for work and recognition long before #OscarsSoWhite was trending on Twitter.

Fiennes got to play Michael Jackson just as white British actor Charlie Hunnam is getting to scoop Chicano actors in playing Mexican American drug lord Edgar Valdez Villarreal, and just as Emma Stone got to beat all Asian and Hawaiian actors to play Allison Ng in Cameron Crowe’s Aloha. Even fictional stormtroopers and witches not even written as white are controversial for actors of color. Meanwhile, white actors can put on black or brown or yellow face for a tidy profit.

Fortunately, Fiennes’ performance will not likely get much appreciation as when it comes to racially passing. White people imbued with white privilege – who seem to be trying to be black only when being black seems advantageous – are likely to receive very little generosity from the public.

Remember the backlash Rachel Dolezal received? The white woman who had sued Howard University for discrimination as a white woman, but who later assumed a black identity who got a job with the NAACP? She was the living example of performing blackness without the history of living in black skin, and having to deal with the consequences of living in that skin whether the skin feels advantageous at any give moment.

The whole world was having none of it and, Dolezal faced a worldwide backlash for using race to her advantage. If and when Elizabeth, Michael and Marlon actually makes it to our screens, I predict Fiennes will face heavy criticisms – and rightly so. Ultimately, there is little doubt in my mind that his performance will be found as inauthentic as Dolezal’s.

• This piece was amended on 28 January to emphasise that the comedy starring Fiennes is a half-hour TV show, not a feature film.