You may wish to contact the celebrity out of a number of reasons: a chance to meet the person, get something autographed, or for business reasons like discussing advertising opportunities. Typically, celebrities don't handle their business deals directly; hence agents are used for booking celebrities for an appearance, concert, endorsement, movie, or similar activities. Publicists deal with anything related to the public, like magazines articles, blogs, and interviews.  Agents, managers, and publicists each have their parts that they represent for a celebrity. They handle the business and image aspects of the celebrity. There are a few different ways of getting in touch with these representatives. The manager’s job is to provide career guidance and advice, and along with the agent (and the celebrity), they’ll need to sign off on any potential deals their client makes. The best way is through email, and it is how most business deals are done with celebrities. Email allows for a paper trail, and it is the preferred method of contact for representatives. Phone is another route to take, but it is not the preferred course of action. Also, it's important to keep in mind that many agents have assistants and gatekeepers, so you will likely be unable to reach the representative by phone. By snail mail isn't a feasible option unless you are sending free product to someone. Even doing this, you want to have spoken to the representative through email or by phone prior to sending your merchandise. Please note that representatives are only to be reached out to for business and publicity inquiries, not for fan mail. Celebrities change representatives frequently. You can monitor these changes through booking agent info databases. A celebrity’s manager is involved in all aspects of their career. Less known celebrities may only have a manager. These people are generally very busy, but can help you contact your celebrity. While the celebrity’s publicist usually doesn’t have much approval power over business deals, they are a...

TL;DR in Vietnamese:
Liên lạc với người nổi tiếng qua người đại diện hay nhân viên truyền thông. Soạn một lá thư phù hợp. Gửi thư.