Cattrall initially rejected for drama
The Sex and the City star, known for her seductive roles, auditioned for the part of Rudyard Kipling's wife Carrie in the drama about how his son (Daniel Radcliffe) went missing in World War One.
But Cattrall has admitted that she had to convince Brian Kirk that she could play more serious parts than her best-known role of Samantha in the hit US show.
She claimed she did not want to play the character because she needed to prove she could act differently, but because she wanted to play a 'real' person that she could research.
Cattrall said: "Well that's not why I picked it and I wasn't actually offered the role immediately. I had to meet Brian and I got a response from my agent saying 'I don't think that Brian thinks that you're right (for the role)'.
"Then he went away and he watched a few films and a play that I did and he said, 'I was wrong, I've changed my mind, I think you'd make a terrific Carrie'. And it was so thrilling for me because for the first time I was playing someone that actually existed, so I had a lot of research to do."
She added: "It was truly one of the most wonderful experiences."