A character, usually male, first meets a stranger, usually female and presumably a future Love Interest, in a dream of his, before meeting her in real life and discovering that she wasn't just an invention of his subconscious. She really is the "girl of his dreams". How did a real person like her end up in his dreams? Maybe they were Prophetic Dreams, or his dreaming of his own time. Maybe it was Telepathy on her part. Or maybe they happened to meet each other's consciousness in a collective Dream Land. Examples: