'Big Brother' Contestant Luke Valentine Kicked Off Show for Using N-Word

'Big Brother 25' contestant Luke Valentine just got kicked out of the house after casually dropping the N-word in the middle of a conversation with other houseguests.

CBS and the reality show's producers tell TMZ ... "Luke violated the BIG BROTHER code of conduct and there is zero tolerance in the house for using a racial slur. He has been removed from the house."

We're told Luke's departure will be addressed in Thursday's episode.

Wednesday morning's live feed captured Luke chatting with contests Jared, Cory, and Hisam as Luke says, "We were in the f****** (inaudible) room, n****."

Luke immediately tried to correct himself by saying "dude" ... and he laughs it off and later tells Jared, who is Black, that it was a slip of the tongue.

Jared didn't seem all too concerned with Luke using the slur, telling him ... "I don't give a f***" ... though it's possible Jared kept his cool for gameplay purposes.