The invention relates to a method of assembly of a turbomachine, in particular of a gas turbine engine, comprising at least a first module and a second module a second shaft assembled by a bearing, said bearing comprising an outer ring shrink-fitted inside a journal integral with the first module and an inner ring integral with the second shaft, according to which the second module is assembled on the first module by engagement of the second shaft, with said inner ring, inside the journal comprising said outer ring, wherein it comprises the following steps: mating the second module with the second shaft up to a determined distance from the journal, centering the second shaft with respect to the journal, said centering being controlled on the basis of measuring distance deviations with respect to a reference on the journal, expansion of the journal by heating its outer surface, completion of the mating of the second shaft.