A theory of the new class was developed by Milovan Djilas, who participated with Tito in the Yugoslavian Revolution, but was later purged by him as Djilas began to advocate democratic and equalitarian ideals. The theory of the new class is in complete contradiction to some communist dogma that a communist revolution resulted in the extinction of any ruling class as such. It was Djilas' observation as a member of a communist government that party members stepped into that role.
Of course, the specific notions of Djilas are his own development, however the idea that bureaucrats in a Marxist-Leninist style state become a new class is not a new idea. Bakunin had made this point in his IWMA debates with Marx in the mid to late 19th century. This idea was repeated after the Russian revolution by anarchists like Kropotkin and Makhno, as well as some communists. It was later repeated by a leader of the Russian Revolution, Trotsky. Mao Zedong also had his own version of this idea. Of course, this wide range of people of the decades and centuries had different perspectives on the matter, but there was also a degree of core agreement on this idea.