Model and actress Laura, 30, bedded Marco, 21, on the Channel 5 show after he claimed to have received a "hall pass" from fiancée Kim.
But Kim isn't happy…
Speaking in the new issue of heat magazine, out now, the fashion designer said: "Anyone who has a fiancée, who has made that commitment – to then pursue them, I think that's the nastiest thing you can do.
"How dare she? It's just f**king rude. She's so disrespectful. I think she's an absolute f**king bitch."
Kim said she'd met some of Marco's exes before: "They're not tarty and chavvy and trashy like she is. She's like a piece of meat, slinging herself across him."
Her wrath wasn't just directed at Laura, however, as Kim also spoke to the mag about how "sick" she felt watching Marco's antics on the show, which have included showering naked with Laura and getting hot and heavy in the communal pool.
Marco's been the most controversial contestant in this year's Big Brother, but his time in the house was short-lived, as he became the first housemate to be evicted when he left on Friday night.
Speaking the following Monday on This Morning, he said of Kim: "The arrangement we had, I was given a hall pass for BB. I was given a free pass to do anything I wanted or what I believed. Maybe I did push it too far and take full blame...
"I am in contact with [Kim] now. I think we've decided to see how it goes over the next couple of weeks and just be friends for the moment. I think Kim's a great person. I don't regret what I did. I shouldn't have done what I did. We spoke about the hall pass before, and I said, 'If it happens, it happens.' She basically said to me, 'Look, I'll give you a hall pass instead of you cheating, I'll accept [that] in case anything does happen.'
"We spoke about it and she knew the situation. She said, 'I'll give you a hall pass, it's fine, I'm not going to be mad, angry… I don't regret anything to do with Laura, I think she's a great person as well. I do feel guilty. I feel bad. I knew [Kim] was watching. In the Big Brother house, you do forget the outside world sometimes. It's crazy in there."
Kim had tweeted during the show: "FYI I said #hallpass NOT open relationship. I don't watch bb, but I heard this today. Worst thing I can't even talk to him #bbuk #bbmarco (sic)."
She did not attend Friday night's eviction.