Normally, a celebrity either has one PR or no PR at all. But there are about two percent (yes, just two percent) celebrities who hire more than one PR. It’s rare though.
The celebrity has to either be very big or extremely diplomatic to have two PRs at the same time. This is because the thoughts and PR strategies of the PRs could clash and the friction could end up affecting the work of the celebrity.
Apart from that, some celebrities hire digital marketing firms along with PR firms.
Whereas PR agencies handle the news media publicity, digital marketing agencies handle social media along with platforms like YouTube, Wikipedia and IMDB updates.
When celebrities are doing films, the films have separate PRs. So most celebrities go with the flow of the film publicists when promoting the film, and adhere to a side-by-side strategy from their personal PR for their individual branding.