I find the industry getting much smaller thanks to Facebook. I attended the SOC awards at which many of the members in attendance were at the time, only Facebook friends. Nw they've become friends and business associates.
Absolutely walk up to the person and say, "hey, we're Facebook friends!" BUT as always, be professional about it. If the person appears to be having an important business lunch--- not the time.
For more tips and articles by top entertainment industry career coach, The Greenlight Coach, visit www.TheGreenlightCoachBlog.com