It's Miss Marple by Agatha Christie. If you are given the chance to pick an ISTJ character on TV that you'd absolutely love, chances are that you'd pick her - if you have watched the show that it.
Katy Perry I'm sure is an ISTP. But her quirky nature (which is probably adopted) is quite similar to the vibe INFPs give. Add to it her strange choice in fashion screams you at me through the screen.