The former X Factor contestant was none too happy with Lewis, after he told her he'd like to see Katie "stand on her own" and not rely on others so much.
Chatting to Katie in the garden, ex-TOWIE star Lewis said: "I think you've been wrapped up in the girls too much. It ain't a bad thing, everyone picks people in here. I think you get a lot of your strength from Aubrey [O'Day]. I get a lot of mine from Marnie [Simpson].
"I find you so interesting and I think you're so lovely, I want to see you stand on your own two feet. It's easy for me to sit and point fingers as I've got all my strength from Marnie and the same for her. I think you're a very cool girl and I love the chats we have, just you and me.
"You have enough about you to stand on your own and stand up and be counted for who you are, not because you're Aubrey's mate or Renee's mate. I think you're good enough to count yourself as a competitor not as an observer or spectator."
Katie countered: "I do feel observing is just part of my personality."
She was clearly pretty peeved with Lewis, later telling Renee Graziano: "I was just paid a really nice backhanded compliment by Lewis to say I'm a follower and don't have my own identity in here. Apparently I follow Aubrey around everywhere and don't have my own identity but that's okay because I'm a really good person."
Lewis faces eviction on Friday night's show against Bear, James Whale, Sam Fox and Ricky Norwood. Two of the housemates will be going home in the first double dumping of the series.
CBB airs 9pm on Channel 5.