Doesn't matter if it's the ML or FL. And the lead has to be out of the ordinary in some way or form. Like maybe they're(as in she or him) "weird" because they've survived a trauma or they have a handicap or similar.
I remember a Chinese drama i watched not to long ago which really fit what I'm looking for, and the ML was basically autistic until he met the FL and they were childhood friends. I don't remember its name though,