Calvin Klein’s Ex-Boy Toy Nick Gruber — Arrested for Coke Possession

Calvin Klein“s special male friend Nick Gruber was arrested for cocaine possession in New York this morning following an altercation with another man  … our sources has learned.

Law enforcement tells us … the 22-year-old model — who used to work in gay porn — was busted at his home at 4:58 AM after someone called 911 to report Nick punched a 20-year-old man in the face.

When cops arrived to the scene, officers say they observed a cut on the victim”s face … and arrested Nick for misdemeanor assault. Cops say Nick resisted by “flailing his arms in the air.”

Cops say they noticed Nick suspiciously reaching into the front of his pants … so they conducted a strip search back at the station … and discovered cocaine on his person.

Nick is now facing 3 criminal charges — including assault, resisting arrest and possession of a controlled substance.

We”re told Nick is still in police custody at the station.

According to multiple reports, Gruber and Klein “dated” for nearly two years before taking a “break” back in January … though Klein has not publicly addressed the relationship. 

Story developing …