Helen Mirren explains why her latest role in 'The Thursday Murder Club' was harder to play than Queen Elizabeth

• Helen Mirren stars in Netflix's "The Thursday Murder Club," available on the streamer on Thursday.
• She said it's harder to play a fictional character than one based on a real person.
• "With the queen, you just have to sound like the queen, walk like her, dress like her," Mirren told BI.

In 2006, Helen Mirren took on a daunting, weighty role: portraying the Queen of England in "The Queen." She was awarded in kind with an Oscar for her efforts.

But Mirren, 80, thinks there are roles that are far more difficult to play than the queen, and her character in her new Netflix movie "The Thursday Murder Club" is one of them.

The film follows a group of amateur detectives cracking cold cases in an English retirement home. As a fan of Richard Osman's book series of the same name, Mirren knew she had to embody the group's no-nonsense ex-spy Elizabeth Best in a way that would engage fans' imaginations.

"With a book that's so popular, there is a responsibility because you don't want to disappoint people who love it. I don't want people watching the movie and going, 'I loved it, but I didn't think Helen Mirren was great as Elizabeth,'" Mirren told Business Insider.

"In a weird way, it's harder to play the imaginary character, especially if it's a character from a beloved book," she added.

"With the queen, you just have to sound like the queen, walk like her, dress like her."

Mirren said she believes she did the role justice and hopes to reunite with the cast, which includes Pierce Brosnan, Ben Kingsley, and Celia Imrie, for a sequel.

"We had a pretty good time together, and I think there was a general feeling that, yes, we would love to do this again if it comes our way," she said.