Behind each celebrity, there's a fully-staffed team or an agency.
A star is one person and can't possibly do everything it takes to propel their image into the cultural stratosphere. The celebrity maintains the status and fame, but the team or agency surrounding them makes the decisions and actually gets things done.
These are the people people need to reach out to when trying to work with celebrities.
In a way, celebrity teams are the invisible army that stands behind the celebrity.
No matter if one is a big or small celebrity, everyone has a team or an agency. It was because they were a necessity if one wanted to succeed in any entertainment industry.
Normally, actors would join agencies as it was way easier to navigate through their career with the connections and power of an agency but a lot of actors also had personal teams.