A followspot is a luminaire designed to be moved by an operator to light a specific performer as they move about the stage.

The best known use is the 'star' of the show being lit in a bright hard edge spot for a musical, pantomine, or concert.... however followspots are often used in a much more subtle way, as a highlight drawing the audience's attention as the action unfolds, typically the beam edge is slightly diffused to blend with the rest of the stage lighting.
 
Operating a followspot is a skilled job, requiring a steady hand, and good anticipation so the spot is always on the performer lighting them, not following them! The operator may have to alter the beam size using the adjustable iris diaphragm and change the colour filter while always keeping the spot steady on the performer.
 
In order to attract the audience's attention the followspot beam must be several times brighter than the rest of the stage lighting. Narrow angle, higher powered tungsten halogen or lower voltage (80V) light sources are typical for smaller stages, drama workshops and school halls with the higher efficency discharge arc light sources (MSR, HMI Xenon) used for longer throws / larger stages.

Operated from the back of a venue or theatre, from an elevated position the followspot produces a narrow beam of light for a long throw (a distance of 30m/100ft - 90m/300 ft).