'T' key isn't working properly

Hi guys. I have a really weird problem with my MacBook Air keyboard.

Sometimes when I go to type the 't' key, it either types two t's at once, or nothing at all. My words either come out looking like 'tthis' or 'his'.

This only happens with the 't' key; I haven't had problems with any others.

I'm really confused here. Does anyone have any ideas on how to fix this?