Having been undercover for years and filtering through the system unnoticed, this could be a huge surprise if Kate is revealed to be working with the H network.
Will viewers get to see Kate and DC Bishop working closely together in season six as they try to bring down the patriarchy?
Speaking of joining the cast, newcomer Shalom said: “Being on set as such a huge fan of the show is such a trip out.
“I was running around, being a fangirl and I don’t know if that’s ever going to wear off,” she told Radio Times.
With seven episodes included in the upcoming season, it seems viewers will get one step closer to discovering who H really is.
Line of Duty season six begins 21 March, 2021, at 9pm on BBC One.