New Big Brother contestant Kinga Karolczak's racy antics have sparked dozens of complaints from viewers just days after she joined the reality show.
Kinga Karolczak entered the house on Sunday
Some 83 people complained to media regulator Ofcom after watching her drunkenly fool around with a wine bottle, bin and blow-up dog.
Channel 4 said the show went out after the watershed and there were warnings.
The 20-year-old entered the house on Sunday to replace Orlaith McAllister, who walked out the previous day.
Monday's action - shown on Tuesday's highlight's show - saw Kinga fondle fellow contestant Craig Coates in the pool and simulate sex with a number of objects.
Channel 4 said it had received "a number" of complaints on top of those sent to Ofcom.
A spokeswoman said: "Kinga's antics went out post-watershed and, as always with Big Brother, there was a voice-over before the programme alerting viewers to the nature of some scenes.
"In tonight's show, viewers will see an embarrassed Kinga apologise to her fellow housemates, explaining she was just having a laugh and nothing happened."
An Ofcom spokeswoman added the regulator would be "looking into" the complaints.
Derek Laud and Eugene Sully are the housemates up for eviction this week.