In scenes cut from last night's latest highlights show on Channel 5, the Blue singer got a little too hands on during a party involving the housemates.
Big Brother rewarded the nine remaining celebrity contestants with booze, food and music after they successfully took part in a (altogether rather cringey) talent show task.
The party antics saw breasts the hot topic for discussion with Luisa admitting she was fascinated by Casey's, saying: "They’re massive! I can’t believe how big they are.”
Later the Apprentice star played a trick on Dappy by using her earrings to make it look as though she had erect nipples.
It prompted Dappy to remark to Big Brother in the Diary Room: "Jees, she’s [Luisa's] got a nice pair of knockers, I think she’s frustrated. I’ve never had two beautiful women next to me both with a perfect set of knockers."
But with the drink flowing, things got a little out of hand later on in the night with a playful Lee pulling down Luisa's pink vest top to expose her boobs... all as the pair danced to Marvin Gaye’s Sexual Healing.
A source said this morning: “In any other environment, this would be seen as an indecent assault.
“Luisa tried to laugh about it but if a man did that to a girl in a club, the police would be called.”
The Daily Star newspaper reports that producers decided to cut the footage out of the show yesterday evening, especially after the complaints similar incidents have caused in the past.
In 2012 Denise Welch got herself into hot water after pulling down the knickers of fellow housemate Karissa Shannon, prompting calls by some viewers for her to be kicked out of the show.
A spokesperson for Celebrity Big Brother told the publication last night that Lee hadn't yet been spoken to over the incident.
Celebrity Big Brother 2014 continues tonight on Channel 5.