The Peaky Blinders star’s death was announced on Friday (16 April) by her husband Damian Lewis, who wrote on social media that McCrory had died peacefully at home after “a heroic battle with cancer”.
Her diagnosis had not previously been made public.
Appearing on the BBC’s Today programme, theatre director Cracknell, who worked with McCrory on productions such as Medea and The Deep Blue Sea at the National Theatre, said that the actor hadn’t wanted news of her diagnosis detracting from her family or work.
“Helen wanted to be very private about her illness and I understand why,” she said. “When you live in the public spotlight you have to find space to protect the things that are just for you.
“Very, very few people knew, and I only did because we were planning to transfer a show to Broadway and we had to cancel that because she was undergoing treatment. We were sworn to secrecy.”
Cracknell continued: “Her need to be fully alive and be committed and to take things incredibly seriously, such as her family and charity work, defined her last few years for her as much as ever.”
Six weeks before her death, McCrory and Lewis had appeared on Good Morning Britain to promote the charity The Prince’s Trust.
The actor’s death prompted an outpouring of love on social media, including from JK Rowling and her Harry Potter co-star Jason Isaacs, the latter of whom described McCrory as “the greatest actress I’ve ever seen”.
Lewis wrote a lengthy tribute to his wife of 14 years on Sunday (18 April), describing her as “a meteor in our life” who remained a “people person” even as her illness worsened.