For a play that makes audience members contemplate their own mediocrity, Amadeus is quite the crowd-pleaser.

Britain's National Theatre has a sold-out hit with a revival of Peter Shaffer's play about bad-boy genius Wolfgang Amadeus Mozart and his jealous rival Antonio Salieri, composer to the 18th-century Viennese court.

The production, which mixes actors, opera singers and a 20-piece onstage orchestra, is being broadcast in movie theaters around the world this month as part of the NT Live series.

First staged in 1979, the play asks an age-old question: Is it possible to separate artists from their art? Shaffer's Mozart is an overindulged prodigy whose divine musical gift coexists with bratty petulance and a fondness for fart jokes.

"He's a spoiled kid," says Adam Gillen, the 31-year-old British actor who plays Mozart.

"But he's accepted because he does this wonderful work. And people are either appalled and disgusted or titillated and entertained."

Gillen, his hair bleached a punkish blond, plays Mozart with manic energy and an underlying fragility. But the real star of the show is the diligent, dignified and increasingly bitter Salieri.

He is "the patron saint of mediocrities", whose tragedy is that he recognizes Mozart's genius and knows he will never match it.

Zimbabwe-raised actor Lucian Msamati tackles a role that has been played by Paul Scofield, F. Murray Abraham and Ian McKellen.

An acclaimed stage performer, Msamati was the first black actor to play the villainous Iago in Othello for the Royal Shakespeare Company. On TV he's played a pirate in Game of Thrones and an auto mechanic in The No. 1 Ladies Detective Agency.

Reviewers have hailed his performance in Amadeus.

Susannah Clapp, in The Observer, called him "a wonderful Salieri: grave, almost carved, you feel him being corroded".

Msamati - who exudes some of his onstage intensity even backstage, wearing a plaid shirt and jeans - says the play's themes "are eternal: love, jealousy, power, betrayal".

Salieri has "done everything right. He followed the rules, he worked hard, he was chaste, he was devout, he was good" - and then he was confronted with a talent far beyond his own.

In the play - based very loosely on real events - Salieri's jealousy triggers a spiritual crisis with deadly consequences. Msamati says many of us can relate to Salieri's sense of anger and betrayal.

The hit revival of Amadeus is a fitting tribute to Shaffer, who died in June at age 90.