cult of personality - intense devotion to a particular person.

from wikipedia:

A cult of personality arises when a country's leader uses mass media to create an idealized and heroic public image, often through unquestioning flattery and praise.^[1] Cults of personality are often found in dictatorships and Stalinist governments.

A cult of personality is similar to general hero worship, except that it is created specifically for political leaders. However, the term may be applied by analogy to refer to adulation of religious or non-political leaders.