What was that movie were the two scientists invent a spray that makes one’s voice irresistible to the opposite?

I watched this over ten years ago. I remember a scene were they tested it on chimps. I remember the woman scientist wore big gles and had poofy hair but ended up with smooth hair and black dress. I remember she had to come rescue the male scientist from the police with her new boy friend and wouldn’t speak because she didn’t want the other scientist to fall in love with her. I remember she got that boyfriend from him hearing her and insisting on buying her a necklace. I remember that the scientists fell in love with each other for real in the end.