Chantelle admits her "heart aches" for ex-husband Preston.
The blonde model - who was married to the Ordinary Boys singer for nine months in 2006 before divorcing in 2007 - admits reuniting with her ex in the 'Ultimate Big Brother' house has been tough for her.
She told former winner Brian: "I do look at him and think... it's almost like my heart aches for him. It's weird.
"But I know that he's avoiding me a bit. Not on purpose. I said to him earlier that he hadn't really spoke to me a lot. But the thing is, it's different. Preston has a girlfriend."
She also praised Preston for treating her "amazingly" when they left 'Celebrity Big Brother' in 2006.
She said: "I think we would have lasted a lot longer if we hadn't got married. But the thing is I was young,
"I was 22, I'd gone on 'Big Brother'... I'd never met anyone like Preston. Give him his due he treated me amazingly. He looked after me. But it all just went a bit wrong. I literally left my mum's on the morning of going on 'Big Brother' and I never went home."
Meanwhile, Chantelle's fellow housemates have aired worries about returning to the series which made them famous.
Former winner Nadia said: "It's a bigger deal doing it the second time around than the first time. It's a scary thing. Things can turn around drastically with my current life. Whatever they pay me it's not enough to move to another country."
Nikki added she was sad to have missed the reunion of her favourite band The Libertines, which led her to question her decision to re-enter.
She said: "I thought, 'Am I making the wrong decision?' "
In a later discussion, Brian admitted he would not have been able to go into 'Big Brother 7' because of Nikki.
He told her: "I was thinking to myself, 'Amazing telly, but I couldn't live with you. It was almost like, 'Oh is she for real? I was waiting for your head to turn 360 degrees like the devil."