'Someone who might knife you' - Mantel on Cromwell
9 March 2014 Last updated at 12:15 GMT
Hilary Mantel, the Man Booker Prize-winning author of Wolf Hall and Bring Up the Bodies, said Henry VIII's henchman Thomas Cromwell, played by Ben Miles in the stage versions of both her novels, is "someone who would knife you".
Mantel said bringing a sense of danger and unpredictability to Cromwell's character in the adaptations of her novels, which are coming to London's West End in May, was essential.
Speaking to Andrew Marr, she added the stripped-down, contemporary language of the characters is not as important as that they "think Tudor thoughts".