The actor currently stars as Italian detective Aurelio Zen in the BBC's adaptation of Michael Dibdin's novels.
"I didn't know [Rufus] personally but I've always loved his work," Andy Harries wrote on the BBC TV blog. "He's very handsome, and rather hip, and has great range as an actor."
He added: "He also has tremendous warmth and humour and brings these great qualities to the role of Aurelio. He just seemed perfect in every way and his time is now."
Harries revealed that he had first thought of Sewell for the role while watching him perform in the Tom Stoppard play Rock 'n' Roll.
"Around the time I was thinking about this show, I went to see the...play," he explained. "As soon as I saw Rufus Sewell on stage, I knew he was the one to play the lead."
The producer went on to claim that author Dibdin "would have been very pleased with the choice".
The final episode of Zen's three-part run airs this Sunday at 9pm on BBC One.