This is when "a client" will typically say, "Well if I didn't know he was in the industry, I probably wouldn't follow up." Okay, I respect your honesty. Most of us have plenty of friends already. However, I appreciate your ability to spot an opportunity.
In the future, if you know the person is in the industry and you don't want to share that you are as well, then treat the conversation "as if" you wanted to continue a friendship with him/her. Then you will know why you're following up, because you'll have discussed the things you have in common, possible plans for a future get together, or a specific plan. I don't mean be phony, I mean, really look for the commonalities.
In this case, because you didn't reveal that you're in the industry you can either:
1. Reflect on your conversation and see if there is a commonality you can build a follow up conversation on.
2. Call specifically to tell him: you're in the industry, what you do, and have a business advice question for him (for which his answer will require you to take action, so you can follow up with him on your results).
For more tips and articles by top entertainment industry career coach, The Greenlight Coach, visit www.TheGreenlightCoachBlog.com