Grace returned to our screens for a fourth series earlier this month, with John Simm's Brighton-based detective tackling a new set of grisly cases.
Yet while millions of viewers were delighted to see him back on ITV1 after an extended wait, some were furious to find the screen adaptations were different to Peter James' bestselling novels.
The second episode in the series, which was based on the book "Want You Dead" and saw DS Roy Grace investigating two puzzling murders, has come in for particular criticism from some quarters of the show's fandom.
However, while there were several key differences to the screen version, Grace star John Simm has defended the alterations to Peter James' novel, which was published over 10 years ago.
"We veered away from the books a little bit in the last series and this year’s series veers off quite dramatically," he told us at a recent press event. "A lot of people who've read the novel won't recognise the second episode 'Want You Dead', which I think is a really good thing."
"If you've read the books, why would you bother watching it?" he continued. "But [the adaption] is different, the characters are different and different things happen to different people, which I think is a really healthy thing for a drama like this."
Simm went on to explain that some changes to the books have been well-received in some quarters...
"DS Bella Moy, who's played by Laura Elphinstone, dies in the books," he explains. "But we didn’t want her to die, so we kept her!"
He also goes on to explain that all the changes are done with the approval of the man behind the books, Peter James, who's currently working on the 21st installment of the popular series.
"He's a big part of that and realises the stories have to evolve," says Simm. "Because fitting an entire book into a 90-minute episode for TV is very difficult."
With 12 of James' books already adapted for the screen and four more currently being filmed for next year's Grace season 5, there are only a few more of the author's novels left for ITV. Yet Simm doesn't think Grace will be coming to an end any time soon..
"Peter is pretty prolific and writes one or two a year," he explains. "But even if we do run out, he's got loads of ideas and storylines we can use!"
Grace continues on Sunday 15 September at 8 pm on ITV
