Quinn was claimed to have upset the Hear'Say singer by getting close to X Factor dancer Sarah Robinson shortly after ending his six-month marriage in April.
An alleged friend of Klass told Now: "It's made her mind race. She's fuming. She told me 'I want to know the truth'."
In response, a lawyer for Quinn insisted that there is no link between the ex-bodyguard's friendship with Robinson and the end of his marriage.
"Graham does know Sarah but he is friends with many people," they told Metro. "Her name has just been put into the frame by somebody.
"This has nothing to do with Graham and Myleene's break-up. He has been subjected to a number of allegations. We don't know who is putting them out there but they are all being denied."
Quinn previously denied a number of "ridiculous" reports about his separation from Klass, arguing that they were making him look "sick in the head".