VIP Characters are special characters you will meet and unlock throughout the game. They are available to work with you alongside projects, just like regular professional contacts. To be able to invite a VIP characters to a project, you will need to invite the specific character into your home and hang out with them. After the hangout is complete, the VIP Character will be available to work with you on a project for the next 24 hours.
The more hangouts you do with a VIP, the better your working relationship with them will be, and the better the rewards they will give when you invite them. Some VIPs are only available to work on specific projects (e.g. modeling), so be sure to check out their specifications in the VIP Contacts tab in your phone .