The teen pop sensation has created a public service announcement with the animal rights organisation to encourage people to give a home to an animal from their local shelter rather than buy a companion from a breeder or pet store.
In the video, which has been posted online, he says: "It`s really important that people adopt. I really encourage going out to an animal shelter or a place where you can get a dog that has been abandoned or doesn`t have a home - A lot of animals are getting abused in different homes ... and I think it`s really important we just stay aware about these different situations."
Justin - who was born and spent his early life in London, Ontario, Canada, before moving to Stratford, Ontario - also reveals he adopted a dog from an animal shelter, a cute papillon breed called Sam.
He explained in the video message: "I have a dog, his name is Sam. He`s actually a papillon. We moved to a city where we didn`t really know anybody, so I wanted a friend and Sam was kind of like that friend.
"My dad and I used to just go visit the different animals and stuff."
The 16-year-old singer also posed for two print adverts to raise awareness of the campaign which include the tag lines "My World Includes Passion for Animals, Yours Should Too," and "Animals Can Make U Smile, Adopt From Your Local Shelter".
Justin is the latest in a long line of celebrities to lend their support to PETA (People for the Ethical Treatment of Animals).
Other stars who have appeared in campaigns or acted as spokespeople include Pamela Anderson, Pink, Leona Lewis, Sir Paul McCartney and Eva Mendes.
According to PETA, between 6 to 8 million abandoned or stray dogs and cats enter animal shelters every year and around half of them have to be euthanized because they can-t be found a home.