Olivia Colman found it ''upsetting'' filming 'Broadchurch'.

The 'Peep Show' actress is set to star alongside 'Doctor Who' actor David Tennant in the new British detective series - which follows the pair investigating the death of an 11-year-old boy on a beach at the foot of a cliff in the seaside community of Broadchurch - and Olivia found herself sobbing as she read through the script.

She recalled: ''I just remember reading it in one go, sobbing, crying, sobbing, crying, oh, it's finished. I don't think I was meant to cry as much as I did. But I found it so upsetting, I just couldn't stop. I usually try not to cry in things, but it's so emotive.''

Olivia explained the storyline tugged at her heart strings even more as she has two children with husband Ed Sinclair and realised how ''horrible'' it must be for parents to lose their kids.

She told The Telegraph newspaper: ''One little crack has repercussions throughout the town, and it's fascinating to follow it. It is very grim, though. I mean, you can't really get worse than the death of a child.

''Most of us have got kids and it's very hard to watch Jodie [Whittaker] and Andrew [Buchan, who play the child's parents] as their faces crumble and they're putting themselves through the emotional wringer.

''You do think about it all the time. The other morning, I was giving my little boy toast and then you stop and realise that the missing child's parents won't be able to do that anymore. It's horrible.''

'Broadchurch' begins tonight (04.03.13) on ITV at 9pm.