The Xtra Factor host said she would be forced to "become a nun" and avoid "eye contact with a male human being again" in order to prevent more rumours about her love life.
"I did NOT go home with Johnny Lloyd last night, same as I did NOT go home with Jordan from the Rizzle Kicks last week," she wrote on Twitter.
"Decided I won't make eye contact with a male human being again. Going to become a nun."
Stephens later joked about the speculation, tweeting to Flack: "It's just 'Rizzle Kicks' there's no 'the' before it. I would expect my wife to know that."
She replied: "@RizzleKicks Damn. Really? I've been calling you that for months. Now, about this marriage...."
Flack previously used Twitter to deny rumours that she is still dating One Direction member Harry Styles, despite him apparently confirming their split in January.
The 32-year-old has also been linked to Xtra Factor co-host Olly Murs and The Only Way is Essex star Joey Essex.