Vilanch, known as a Hollywood jokeman non pareil and as the current Edna Turnblad in Hairspray, will play Zeus, the king of the Greek gods.
He joins Eden Espinosa, Alice Ripley, Cary Shields, Brandi Chavonne Massey, Klea Blackhurst, Will Swenson and Shannon Connelly at the Canal Room event.
Johnson's collaborators on the project include fellow musician, Brendan Healy, and the book writing team of Dick Clement and Ian La Frenais, screenwriters of the film "The Commitments." The score is described as a mix of rock and roll, R&B and pop.
As the title amply suggests, the show takes as its inspiration from the classical tale of Helen, for whom a thousand Greek ships sailed to war against Troy.
His background notwithstanding, Johnson said in a statement, "I love musical theatre, especially the classic stuff, like Rodgers and Hammerstein."
For tickets ($25) to the reading, call (212) 868-4444 or visit Smarttix.com.