Peter Morgan, who the star has been in a relationship with since 2016, is the creator and writer of the Netflix drama.
“He asked me whether I thought that I could do it,” Anderson told The Zoe Ball Breakfast Show.
“And then when I said that I thought I could, he talked to the casting director Nina Gold, who informed him that I was already on the list.
Never underestimate the outsider.
The Crown Season Four. Now Streaming. pic.twitter.com/WI5zzG1J3h
— The Crown (@TheCrownNetflix) November 15, 2020
“They fortunately had the same thought. Not quite sure why, but I’ll take it as a compliment,” she told the BBC Radio 2 show.
Anderson has previously discussed working with her partner.
“For our sanity, and actually for the benefit of the relationship, we had very clear boundaries: ‘I am not going to comment on the script, but you are not allowed to comment on the performance,’” she told Harper’s Bazaar.