Yes you need to use the 30 second opener as described above for these types of situations.
"Hey I just saw you <doing something> I'm just about to meet my friends but would kick myself if I didn't say hi to you. I know nothing about you I don't know you who you are, I almost feel weird liking you, but would like to get to know you better".
"Hey I just saw you <doing something> I'm just about to meet my friends but would kick myself if I didn't say hi to you. I know nothing about you I don't know you who you are, I almost feel weird liking you, but would like to get to know you better".