parasocial
One-sided (especially of a relationship, as for example that between a celebrity and their audience or fans, whom they do not know).
a parasocial relationship
Where it comes from
From para- + social, coined by American sociologist Richard Wohl, together with American anthropologist, sociologist, and communication researcher Donald Horton in 1956.
Adapted from the Wiktionary entry parasocial (CC BY-SA 4.0).