A video produced by 20th Century Fox to promote low-budget horror 'Devil's Due' is officially the most viral movie ad of the year so far.

The short video features a robotic demonized baby in a pram terrifying unsuspecting people in the streets as they walk, and go about their daily business.

So far, the video on Youtube has been viewed over 40 million times, and also includes a behind-the-scenes feature showing how the 'Devil Baby' is set up to scare.

Produced on a budget of around $7 million, the horror film went on to gross over $36 million world-wide, starring Zach Gilford and Allison Miller.

Is this the best movie marketing video campaign of the year?