Netflix has refused to confirm reports about the casting, but it is understood that Staunton is in discussions with Left Bank Pictures over the role, though a deal is still some way off being completed.
The Crown was renewed through season 4, but has not yet gotten an official green light for seasons 5 and 6. However, creator Peter Morgan signed a huge overall deal with Netflix in October, with sources telling Deadline it will encompass another two seasons of the show.
“We are currently filming season 4 of The Crown but have not commissioned any further seasons as yet, therefore any news on casting remains pure speculation,” a Netflix spokesperson said in a statement.
Season 3 of The Crown, which launched on Netflix last weekend,