Katherine Heigl bares all for animal campaign

Dog lover Katherine Heigl has posed semi-naked with nothing but a puppy to protect her modesty in a saucy new advertising campaign.

The actress covers her breasts with a dog in the new public service announcement for website IHateBalls.com, which urges pet owners to spay and neuter their furry friends.

The Knocked Up star wears nothing but panties, high-heeled shoes and a grin in the provocative video, joking, "Unfortunately I can't cut the nuts off human men - yet. So I've dedicated my time to the neutering of dogs because that's legal."