 In the years to come, Nelepp would collaborate with composers of Soviet operas, who valued his real experience of the conditions they were theatrically depicting.In 1944, Nelepp left the Kirov to join the Bolshoi Theatre in Moscow, where he performed until his death from heart disease in 1957 at the age of 53.With a repertoire of 50 roles, Nelepp sang the dramatic tenor parts in classical Russian operas including the title role in "Sadko", the Pretender in "Boris Godunov", Gherman in "Pique Dame", Czarevitch Guidon in "The Tale of Tsar Saltan", Sobinin in "Ivan Susanin", Yuri in "The Enchantress", Finn in "Ruslan and Ludmilla", Tucha in "The Maid of Pskov", Toropka in "Askold's Grave", Jontek in "Halka", Jenik in "The Bartered Bride", Andrey in "Mazeppa", Vakula in "The Slippers", and Golitsin and Andrey in "Khovanshchina".