This is an extra diegetic gaze, where the actor or actress talks or look directly at the camera, so it seems they are talking to the audience individually. It gives a connection between the film star and viewer and allows the viewer to sympathise with the character because the character is looking the viewer right in the eyes (camera lens).
shot types and examples
Depth of field in pulp fiction, the use of this effect creates a focus on the character and helps the audience to concentrate on just the characters emotions by blurring out the background and focusing on the characters face.
Subjective camera shot in the incredible hulk. In the start of this scene the camera shows the soldiers running up some stairs Kinetic camera shot showing us a 1st person shot so it feels like we are in the action and allows the viewer to be more involved in the film and feel emphasise with the character more.