Luke Treadaway passed the time on the set of new crime show Thirteen Steps Down with a spot of grave-digging.

The 27-year-old plays disturbed loner Michael 'Mix' Cellini, who ends up murdering an unfortunate date in the ITV1 show, based on Ruth Rendell's novel.

And Luke revealed he ended up digging the young victim's grave himself.

"Rather than stand around waiting for the next shot to be ready and getting cold I thought I might as well keep myself busy and dig the grave," he said. "It'll hopefully be the only time I ever do it!"

The actor admitted it was both a joyous and a draining task to play such a dark role.

"The days spent playing someone suffering from mental illness and the complete derailment of their mind can be draining, but that's not a bad thing," he explained.

"A part that gives you the opportunity to look at someone's mind like that is good, but it's not necessarily really fun all day every day!"

When asked how he switched off in the evenings, he joked that he "kept away from the kitchen knives," before adding: "You've got to go home and look at what you're doing for the next day so there's not a lot of down time, but luckily it was only for four weeks."

:: Thirteen Steps Down begins on on ITV1 on Monday August 13.