The original model used in Steven Spielberg’s classic 1982 film ET is expected to fetch up to $3m (£2.6m) when it goes under the hammer in December.
Predating CGI technology, the mechatronic features 85 points of movement and was operated by twelve professional animators.
Regarded as an engineering masterpiece, it was originally created by Italian special effects designer Carlo Rambaldi.
The sale of the model is part of the Icons and Idols: Hollywood auction, organised by Julien’s Auctions and Turner Classic Movies (TCM) which coincides with the film’s 40th anniversary year.
ET The Extra Terrestrial was nominated for nine Academy Awards, winning four including best visual effects, which was awarded to Rambaldi and his team.
It starred Henry Thomas and Drew Barrymore, and featured a score by legendary composer John Williams.
Other items from the film that will go up for sale at the auction include the original ET maquette model made for Steven Spielberg to approve the ET design, which is estimated at between $80,000 and $100,000 (£70,000 – £87,000).
A series of original ET blueprint mechanical illustrations are also estimated at between $10,000 and $20,000 dollars (£8,600 – £17,000) each.
Elsewhere, items from the Harry Potter franchise are also expected to fetch hundreds of thousands, including a selection of prop broomsticks belonging to Daniel Radcliffe.
The models include the original Nimbus 2000 from Harry Potter And The Philosopher’s Stone, which could go for up to $100,000 (£87,000), and a Shooting Star prop broom, which is estimated at between $30,000 – $50,000 (£26,000 – £43,000).
An original Gryffindor wool overcoat and red and yellow Gryffindor scarf designed for Harry Potter is priced at between $20,000 – $30,000 (£17,000 – £26,000).
A Gryffindor Quidditch team stunt robe from Harry Potter and the Chamber of Secrets may fetch up to $20,000 (£17,000).
The Icons and Idols: Hollywood auction is due to take place live on Saturday, December 17 and Sunday December 18 in Beverly Hills.