The white British star of Shakespeare in Love plays the black King of Pop in Elizabeth, Michael & Marlon, alongside Stockard Channing as Elizabeth Taylor and Brian Cox as Marlon Brando.
The script is based on a - possibly fictitious - road trip the three stars are rumoured to have made in an attempt to leave New York after the September 11 attacks.
Sky Arts, which commissioned the drama, confirmed the casting and said on Wednesday that the show is in post-production and is due to air in 2016. The channel said that it was "part of a series of comedies about unlikely stories from arts and cultural history."
MJ had vitiligo, a condition that causes patchy loss of skin pigmentation, and his complexion lightened dramatically as he grew older. He died in 2009 aged 50.
The casting news comes amid a debate about lack of diversity in Hollywood, sparked by an all-white slate of Academy Awards acting nominees. (Also Read: #OscarsSoWhite: Will Smith to Join Wife Jada Pinkett in Boycotting Show)
Iranian-British comedian Shappi Khorsandi tweeted:
Joseph Fiennes is playing Michael Jackson? Fab. Now we can all shut up about lack of diversity.? Shappi Khorsandi (@ShappiKhorsandi) January 27, 2016
Sky said the network "puts the integrity of the creative vision at the heart of all its original commissions."
"We believe in giving producers the creative freedom to cast roles as they wish, within the diversity framework which we have set," Sky said in a statement released by a spokeswoman.
Mr Fiennes' agent did not immediately respond to a request for comment.