The singer took to Twitter to respond to articles that claimed the building magnate had filed for divorce.
In a series of tweets, which have since been deleted, she said, "The story is untrue. Sam has not filed for divorce citing infidelity, neither have I.
"Wherever it came from, it's a lie... Why @GraziaUK would choose to run this libelous story where children are involved, without even checking is beyond comprehension."
In another post - in response to a user who shared one of the articles - Allen insisted the rumours were "not true".