The Big Brother 7 contestant, who says that Crouch asked her to sit with him in a booth at the Chelsea club, also revealed that the footballer's actions drew a furious response from Clancy, who apparently threw a bottle at him.
Horgan-Wallace told Reveal: "He asked, 'Can I take you to dinner? Do you want to come to my house? Can I have your phone number?'
"I was completely gobsmacked. I couldn't believe he had the audacity to come on to me while with his girlfriend.
"I said to him, 'You've got a girlfriend.' Peter said, 'Yeah, that doesn't mean I'm happy though, does it?'"
When Clancy saw the pair, she reportedly told Crouch: "Pete, I hate you! What the f**k are you doing?"
Horgan-Wallace said that she promised Clancy nothing was going on between them, to which the model replied: "Shut up, they all f**king say that."
According to the Big Brother star, Clancy then hurled a bottle in the direction of Crouch.
Clancy has reportedly decided to forgive her fiancé following reports earlier this month that the England striker paid £800 to sleep with a teenage escort in Madrid.