Little Mix fifth Member!! L.T fanfiction

There is a simple girl named Katnis walls. But everyone call her kat for short.
She's 20 years old. Lives in england and a very good in singing.

She actually wants to be a actual singer. Specifically in a band.....

What will happen if katnis. Joined little mix as a fifth member. And will Louis find love. During the there tour together with little mix.