Macavity is the villain of the story, who kidnaps Old Deuteronomy.
Richard Pettyfer first brought the character to life in the original West End production.
It's not the only project Elba will be channelling his inner bad guy for - last week, ends October 12, he jumped onboard The Rock a.k.a. Dwayne Johnson and Jason Statham's "Fast and Furious" spin-off, "Hobbs and Shaw", in which he will also play the foe.
"I learned a long time ago... that heroes are only as great as their greatest villains," Johnson, aka The Rock, wrote on Instagram, alongside a photo of Elba in action.
"A pleasure to introduce the man himself @idriselba we brought in to our Fast & Furious franchise to wreak havoc, hell and mayhem on our heroes HOBBS & SHAW."
Revealing Elba's character will be known as the undefeated Brixton, he promised fans the "SHOWDOWN OF ALL SHOWDOWNS."
"So cool having my brother @idriselba come and play in our sandbox," he added. "This one's been years in the making!!"
"As I always say, we either gonna get along or we gonna get it on... and f**k getting along."
Responding to the warm welcome, Elba replied on his own social media post, "Excited to wreak havoc, hell and mayhem on @therock and @jasonstatham in #HobbsAndShaw as one of the most bada** villains the Fast & Furious franchise has ever seen!"
"Feels amazing to be working with @therock and @jasonstatham and to be joining the Fast & Furious family. Coming SUMMER 2019."