The 34-year-old was blasted by her ex-fiancé Adam Thomas last week, after it was revealed she and Paul, 38, are back together.
S Club 7 stars Hannah and Paul enjoyed a five-year romance during the height of the band's fame, but split up in 2006.
Adam has claimed Hannah dumped him as soon as the band reunited this year, telling The Sunday People: "He’d moved into my bed before it’d got cold – that’s the biggest kick in the teeth."
But Hannah has dismissed his claims and insisted that she and Paul are happy together.
She said: "We're not bothered. No one is going to ruin what we have. We're really happy together. Everything is great."
Hannah also revealed S Club's fans are overjoyed that she and Paul have reunited.
She added: "The reaction from fans has been great. We've had lots of messages from people saying they're glad we're back together. It's so nice."