An HBO outdoor ad in which a short film allowing passers-by to watch goings-on inside eight apartments was projected on to a building last night won a grand prix award at the Cannes International Advertising Festival.

The campaign, by ad agency BBDO New York, featured a four-minute film projected on to the side of a building that allowed "viewers to become voyeurs watching eight different apartments encompassing life, death and everything in between".

HBO picked up the grand prix award for outdoor advertising in Cannes for the projection installation, titled "Voyeur".

The US cable network has already picked up one grand prix award for the campaign in the Cannes festival sales promotion category.