From Beatlemania to Swifties—and now the fandom surrounding the new hit show Heated Rivalry—fan culture continues to evolve in powerful ways. HBO’s latest hit centers on a steamy romance between two rival hockey players, whose on-ice aggression hides a passionate private relationship.

The show has earned widespread praise and has even been credited with drawing new audiences to hockey games across the country.

Fans are following the show’s stars wherever they go, openly sharing how the series has taken over their lives. Social media is flooded with commentary, devotion, and emotional investment that goes far beyond casual viewing.

But some experts are raising concerns that this kind of real-life fandom can cross a line into obsession—what psychologists refer to as a parasocial relationship. A parasocial relationship is a one-sided emotional bond in which someone feels a deep personal connection to a media figure who does not actually know them.

Clinical psychologist Dr. Jen Hartstein of Hartstein Psychological Services joins NBC News to discuss why Heated Rivalry is having such a powerful impact, what drives intense fan attachment, and the psychology behind parasocial relationships with influencers and public figures.

Watch the full interview now to learn more about the emotional pull of modern fandom—and when admiration can become something more.