The male rider was being treated by paramedics at the scene after the smash at the junction between Back lane and Cumberagh Lane in Whittingham near Preston.
But less than two hours after the incident, at 3.25pm, police have confirmed the man has died.
Lancashire Fire Service and North West Ambulance Service are both at the scene and no update has been given at the driver or potential passengers in the car involved.
Both roads are closed in both directions and police are asking motorists to avoid the area.