If the person is so well known, it's probably possible, through asking around, to get a little first-hand information about them. Depending on how you like to approach people, you may or may not want to find out what the person's personal reputation is, but you absolutely should be up to speed on their recent work. Think about what makes you comfortable and try to work with that. Keep in mind that the odds are in your favor. Part of the fun of being an established senior person is that people do know who you are and seek you out.
Most people enjoy having their ideas sought out.
Be prepared to say a little bit about your own background, so there's a context for your interest in the other person. If you have an agenda, be direct about what it is. Some initial small talk is fine, but be prepared to be clear about what you want. If you end up in a discussion in which you say you'll send a copy of something to the person, do so promptly and include a brief note which makes reference to your conversation. Career Services, University of Pennsylvania.