Last week’s Academy Awards saw Fennell pick up the Best Screenplay trophy for her revenge thriller Promising Young Woman.
According to The Mirror, Williams will star opposite Dominic West, who is reportedly in late-stage discussions to replace Josh O’Connor as Prince Charles.
Williams and West will be joining a star-studded cast, including Imelda Staunton (the Queen), Jonathan Pryce (the Duke of Edinburgh), Lesley Manville (Princess Margaret) and Elizabeth Debicki (Princess Diana).
The 52-year-old studied drama at the Bristol Old Vic Theatre School after which she joined the Royal Shakespeare Company.
Williams made her film debut in 1997’s The Postman, followed by an appearance in the beloved independent comedy Rushmore in 2001.
In 2009, she played the English teacher to Carey Mulligan’s character in An Education. Later, Williams starred in Roman Polanski’s political thriller The Ghost.
Williams also appeared in Joss Whedon’s short-running show Dollhouse. More recently, she teamed up with the director for his new sci-fi series The Nevers, which is available to watch now on Sky Atlantic.
Production on season five of The Crown is due to begin in June 2021, which marks more than a year since filming concluded on season four.
Unexpectedly, The Crown was always intended to pick up filming this summer, despite speculation that the Covid-19 pandemic had delayed production.
This means that viewers will likely have to wait until 2022 for the next series.