Anna & Methadone Doc -- Down and Dirty

TMZ has obtained shocking video footage of Anna Nicole Smith and a shirtless Dr. Sandeep Kapoor getting hot and heavy at a West Hollywood, Calif. gay bar in 2005.

Both Larry Birkhead and Howard K. Stern can be seen looking on as Anna gets groped and licked by Kapoor, who is currently the subject of an inquiry by the California Medical Board over his possible misconduct in the prescribing of methadone to an alias used by Smith.

As TMZ first reported, a prescription for methadone was written by Dr. Kapoor on August 25, 2006 for "Michelle Chase," a known alias of Anna Nicole Smith, who was eight months pregnant at the time.