A small, private funeral service has been held for the married Long Island doctor who suffered a fatal apparent cocaine overdose while partying in Manhattan last weekend.

The family of Dr. Kiersten Rickenbach Cerveny held the funeral sometime this week, sources said.

“It already happened. It was a private service,” said a worker who answered the phone Friday at Fairchild Sons Inc. funeral home in Manhasset, Long Island, Cerveny’s hometown.

“Only the immediate family were in attendance.”

The employee refused to answer any other questions.

On Sunday morning, the 38-year-old dermatologist and mom of three was found unconscious in the doorway of a Chelsea apartment building, where police sources have said she went on a deadly drug binge with married HBO producer Marc Henry Johnson, 51.

Floral arrangements and catered food were delivered to Cerveny’s Manhasset home Friday.

She was married to fellow dermatologist Andrew Cerveny.