A display apparatus comprising: a receiver (no) configured to receive a video signal; a video signal processor; a display unit; a controller configured to control the video signal processor to determine whether the received video signal is a two dimensional, 2D, video signal or a three dimensional, 3D, stereoscopic video signal and which, in response to a determination that the received video signal is a 2D video signal, controls the display unit to display the received 2D video signal, and in response to a determination that the received video signal is a 3D stereoscopic video signal, controls the video signal processor to convert the received 3D stereoscopic video signal into a converted 2D video signal and controls the display unit to display the converted 2D video signal; wherein, after the converted 2D video signal is displayed, the controller controls the display unit to display a 2D / 3D conversion User Interface, UI, allowing a user to select the display of a 3D stereoscopic image or the display of a 2D image, the 2D/3D UI being displayed along with the the converted 2D video signal, and wherein, in response to receiving a user selection using the 2D / 3D conversion UI through a user input unit, if the display of a 3D stereoscopic image is selected, the controller controls the display unit to display the received 3D stereoscopic video signal, wherein the controller is configured to in response to a determination that the received 3D video signal is received by turning on the display apparatus or by changing a channel, control the video signal processor to convert the received 3D stereoscopic video signal into the converted 2D video signal and control the display unit to display the converted 2D video signal. a receiver (no) configured to receive a video signal; a video signal processor; a display unit; a controller configured to control the video signal processor to determine whether the received video signal is a two dimensional, 2D, video signal or a three dimensional, 3D, stereoscopic video signal and which, in response to a determination that the received video signal is a 2D video signal, controls the display unit to display the received 2D video signal, and in response to a determination that the received video signal is a 3D stereoscopic video signal, controls the video signal processor to convert the received 3D stereoscopic video signal into a converted 2D video signal and controls the display unit to display the converted 2D video signal; wherein, after the converted 2D video signal is displayed, the controller controls the display unit to display a 2D / 3D conversion User Interface, UI, allowing a user to select the display of a 3D stereoscopic image or the display of a 2D image, the 2D/3D UI being displayed along with the the converted 2D video signal, and wherein, in response to receiving a user selection using the 2D / 3D conversion UI through a user input unit, if the display of a 3D stereoscopic image is selected, the controller controls the display unit to display the received 3D stereoscopic video signal, wherein the controller is configured to in response to a determination that the received 3D video signal is received by turning on the display apparatus or by changing a channel, control the video signal processor to convert the received 3D stereoscopic video signal into the converted 2D video signal and control the display unit to display the converted 2D video signal.