Who is "The Stig"?

"The Stig" is the creation of BBC television show Top Gear. This solely purposed mysterious entity is introduced to conduct specific segments by hosts Jeremy Clarkson, Richard Hammond and James May. His purpose on Top Gear is to attempt a fastest lap time in the car featured on that episode. "The Stig" name is used here to indicate our reviewer is a nameless entity with the sole purpose of writing energy drink reviews. This is not really "The Stig". Or is it?