Yes, that line is going to work.....
The "I think I've seen you before??" -line is good, coz when the person is thinking "where the hell do i know you from?" ---you can suggest some events, places,.....and she/he can only respond "yes I have been there", or "Did you go there too?"or "no, I don't remember you" (and she/he will feel bad that he/she doesn't remember and start an Interactive conversation, which is better than a "bugger off", "I am not interested", "go to hell" and the like!!!
It happened to me once in a club, and I really believed him, and I felt bad that I could not remember him, so I chatted with him to try and remember.....however, he was not my type....