Would this be unprofessional?

This summer I have at job at a summer festival selling merch for local bands. The band that I'm selling merch for is friends with the guitarist of my favorite band, and I've heard rumors that he might show up. So my question is, since I'm just the merch girl and since I'm only there to work, would be unprofessional for to me to go over and say hi, in the event he did show up. I'm NOT fan girl, and I'm not interested in getting a picture or autograph or anything like that. I just want to say hi, and tell him that I enjoy his work. I'm going in to the job with the mentality that I can't or won't say anything. I just want to know your thoughts. Would this be inappropriate?