Rooney Mara has teamed up with global farmed animal advocacy organisation, Animal Equality, working on an undercover investigation inside two British factory farms, examining 'the harsh and painful reality' for billions of animals who're 'raised for meat, languishing in abhorrent conditions'.

The US actress, who narrates the With My Own Eyes film, said 'Nothing prepares you for looking into the eyes of a mother pig whose life is to be impregnated and left in a cage until she's slaughtered... I can't imagine how awful it must be to be literally trapped and crushing your own babies and not be able to do anything about it'.