The model told her 147,000 followers that she was not a "home-wrecker" and called out trolls who told her to "hang" and "kill" herself.
Last week it emerged that Rhian - who is engaged to actor Oliver Mellor - had been back in contact with TV presenter Vernon, whom she previously swapped flirty texts with back in 2010.
Rhian wrote in a lengthy Instagram post: "I have a fiancé called Oliver. Sorry to p*** on your chips but we ARE still together.
"I am NOT a home wrecker, Porn star, escort, gold digger OR Stripper! I get paid to model and have done for 10 years. I own two cats and live in a two up two down, minding my own business!"
She continued: "Keyboard warriors... I have no intentions of hanging or killing myself! I have a life to live! Top tip… try and live yours too!
"PS – Don't believe EVERYTHING you read!"
Rhian's Instagram message comes after Oliver hit back at claims the couple had broken up by sharing a photo of them in bed.
"If your 'story' is true then who the f**k is this in my bed??" he wrote.
TV presenter Vernon issued a statement last week denying ever sending any "inappropriate" messages to Rhian, explaining that his wife Tess Daly was "aware" of their exchanges.
He said: "I was contacted by Rhian out of the blue back in December regarding the story in 2010 claiming she had information she wanted to pass on. I recognise how it may look when messages are pulled out of context but there was never any inappropriate intent to our communication.
"I was merely trying to find answers to questions that I've had since 2010. Tess is aware of everything that has been discussed with Rhian."
However, Rhian broke her silence after a few days later, telling The Sun: "I'm not being labelled a home wrecker. The only person responsible for wrecking Vernon"s marriage is Vernon himself."
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