Sir Ian McKellen has spoken about "all th'addition to a King". He believes that Shakespeare refers to Lear's divine right to rule, thus making his renunciation of the kingdom even more impetuous. He desires to keep his God-given right to rule, but not to put it to any effect.
The part of The Fool was previously played by Sir John Hurt in King Lear (1983). Hurt played another of Sylvester McCoy's best-known roles: the Doctor on Doctor Who (2005). McCoy played the seventh Doctor, while Hurt played the War Doctor.
Sir Ian McKellen and Sylvester McCoy appeared in The Hobbit trilogy, playing the wizards Gandalf and Radagast, respectively. Sir Michael Hordern also played both Lear and Gandalf.