A lethal cocktail of drugs known as “Calvin Klein” has swept the nightclub scene amid reports that a 17-year-old London-born violin prodigy died from the dangerous combination.

Experts warn that “Calvin Klein” binges, which involve ketamine and cocaine, “wreak havoc on the brain’s chemical system and can greatly impair overall brain functioning,” according to a site dedicated to treating ketamine substance abuse.

The party drug — with Calvin standing for cocaine and Klein referring to ketamine — produces a euphoric high similar to ecstasy, users claim.

The US National Center for Biotechnology Information said the deadly mix has become “popular among young drug abusers” and has been associated with an “increased risk of human immunodeficiency virus (HIV) infection,” though the study didn’t provide an explanation for the link.

The drug combo killed Katya Tsukanova, who fatally collapsed June 18 at her Kensington home from an apparent overdose — and her family is now warning others about the drug craze, the Telegraph reported.

Her Russian billionaire father, Igor Tsukanov, said his daughter was a “smart girl, and she made one bad choice” as the drug’s popularity surges with young people.

“What can we parents do? The children will do what they want anyway, and they never tell you the truth,” he told the news outlet.

The late teen’s pal, who asked to remain anonymous, said the drug combo was the “new thing among Katya and her friends.”

“Not just them, though — it’s everywhere,” the friend told the Telegraph.

In the wake of the violinist’s death, social media users questioned whether the party drug’s “sexy name” played a role in its popularity.

“They should call it grim reaper to discourage kids,” one Twitter user wrote.