Andrew Garfield was originally cast as Frankenstein's Monster, but had to drop out due to strike postponements that led to scheduling conflicts. He was replaced by Jacob Elordi.
In a previous reincarnation of this production it was planned as part of a new franchise of remakes of traditional Universal Studios monster universe including Dracula Untold (2014). and The Mummy (2017). It is now intended as a standalone film as always planned by film director Guillermo del Toro.
As early as the late 1990's to early 2000's actor Doug Jones was attached to play the monster. Jones has worked with Del Toro in many films including The Shape of Water and Pan's Labyrinth.