His identity is the subject of feverish speculation in the media, fuelled by his regular appearances at West End opening nights in costume, wig and latex mask.
He has become a genuine theatre impresario, launching talent competitions Search for a Twitter Star and its successor, Search for a Twitter Composer.
And now West End Producer is ready to share all he's learnt about how to get ahead in showbusiness, in the form of a handy paperback book: Everything You Always Wanted To Know About Acting (But Were Afraid To Ask, Dear).
Full of the wit and mischievous indiscretion that has gained him such a cult following, packed with gossip and insider knowledge of the theatre business, and containing enough savvy advice on acting to kickstart a career, West End Producer's book offers tips (both practical and deliciously impractical) on:
Getting into drama school (learning how to sit in a circle)
Auditioning (perfecting the neutral vacant stare pose)
Rehearsals techniques (including how to act in a serious play)
The different kinds of actor (from sex pest to company idiot)
Combating boredom (and avoiding backstage naughtiness)
How to behave at first-night parties (obeying the traffic-light colour code)
And, most importantly, the correct way to bow at the curtain call.
Also included in the book are many of West End Producer's most memorable tweets, miniature comic salvos despatched with all the shrewdness of a man who truly knows his Barrowmans from his Balls.