The actor starred as a young Queen Elizabeth in the first two seasons of the Netflix hit - which aired in 2016 and 2017 - and won an Emmy for her performance.
With the monarch ageing as the story about the royals went along, Olivia Colman stepped into the role for the following two series and Staunton took over for the fifth, which was unveiled in November.
Asked on The Graham Norton Show about reprising the role, she said: “I went back and did it again because it is a lovely thing to do and I really love Imelda (Staunton)."
"I think she is amazing," she added.
The star, 38, also talked about her Oscar-nominated film Women Talking, which is about women living in an isolated Mennonite community.
She had to keep things very simple when it came to her costumes and admitted that not shaving her legs while she shot the film was “horrible”.
“We had no hair and makeup at all and wore polyester dresses so what got us through filming was the thought of a party at the end when we could wear makeup and shave our legs,” she said.
“I thought not worrying about shaving would be a real moment of empowerment but actually it was horrible and reminded me of puberty!”
The Graham Norton Show is on BBC One on Friday 27 January at 10.40pm and is also available on BBC iPlayer.
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