The TOWIE star was said to be larking around in the garden with model Sophie when he whacked her a bit too hard and she complained.
Mario was then hauled into the Diary Room and told his behaviour was unacceptable, a move that hints bosses are still on alert following the recent normal series of Big Brother.
Last month, Daley Ojuederie was removed from the house after slapping fellow contestant Hazel O'Sullivan and being aggressive towards her.
According to the Daily Star, the scenes between Mario and Sophie will not be aired in the C5 show tonight.
The newspaper has quoted Mario as telling Big Brother: "We were just f***ing around and having fun."
Sophie, who also spoke to BB, said: "He did it a little bit too hard. They think this is serious but we were just play fighting."
Last night, Mario was shown telling Sophie how beautiful she is after having a few drinks.
He said: "Sophie, if you were single, different story, trust me, you're awesome. You're beautiful, you're so beautiful. So, so beautiful. You're so beautiful..."
Check out this year's housemates in our gallery below!
Are you enjoying this series of CBB? Tell us below, as the best comment from across the website each week wins £50.
Copyright: Channel 5