Confused identities, polar opposites, celebrity culture--sounds like the makings of a great comedy.

This is a good one. Somebody run with this!!

Liz Lemon: "Mamma Mia! It's Mamma Mia!".

or

A celebrity doesn't want to meet their once non-existent father. But continuously searches out father figures. Will celeb end up giving their father the last chance he needs to fix it all.

or

A friend/manager of a famous actor takes it upon him/herself to find the possible father of his client. But it turns out that it's the manager who finds what he's been looking for.

or

Similar to the movie Father's Day. Two knuckle head possible fathers battle for a celebrities affection and in hopes of being the actual father. On this journey, will they reach the goal together or will it be a no holds barred battle?