London-based web specialists Hot Cherry will promote All About Pets, the animal charity's new online hub for pet owners.
The site, which is currently in beta phase, will allow members to create profiles for themselves and their pets, discuss animal-related topics in forums and rate each other's photos and videos.
The charity will also offer animal owners advice via All About Pets, with users able to print off leaflets and articles on subjects including cat health and caring for horses.
Hot Cherry will work with The Blue Cross' in-house comms team to promote the new social network across TV, radio and print, as well as targeting online media and bloggers.
The pet charity's head of comms Debbie Curtis said the aim of All About Pets is to 'engage and interact with a 21st century audience'.