Helen: Said attraction to Paul began in the third week
Paul, 25, and Helen, 23, gave an interview to Heat magazine to make their relationship public.
Viewers of the Channel 4 reality TV show were hooked by their flirting inside the house, and the pair have been the subject of intense tabloid attention since the show ended in July.
Although air steward Brian Dowling won the show's £70,000 prize, Paul and Helen's romance has overshadowed news about the other former housemates.
Bookmakers slashed the odds on the couple marrying from 10-1 to 6-1 the day after Helen left the house as runner-up.
Some commentators have put recent increased tabloid newspaper sales down to the frequency with which Helen has appeared on their front covers.
Two contestants from last year's first Big Brother series, Tom McDermot and Claire Strutton, have also become a couple and are now expecting a baby, due at the end of the year.
"I've never looked into a bloke's eyes before and saw all the lights flashing past."
She said she first began to feel that way after three weeks in the Big Brother house.
"I can honestly say I've never felt like this about a girl before," Paul told the magazine.
"There's something here that's a little bit special."
The pair revealed they decided to get together one week after the show ended, but accused the media of trying to create rifts between them for the sake of stories.
"We know what we want - to have a relationship with one another - but the climate at the moment seems to be that they [the media] are trying to play us off against each other," added Paul.
Paul has been pictured being kissed by a model, but argued that newspapers had blown it out of proportion.
Helen, from Cwmbran, south Wales, said they had decided to give the interview after becoming fed up with journalists hounding her.
She praised Paul as a "nice, honest, genuine guy".
"Paul's got nice cheekbones, nice clothes, and all my other boyfriends have been bad," she added.
Former hairdresser Helen also confirmed she was to host a new health and beauty slot on Lorraine Kelly's daytime show on Sky TV.
Paul revealed he would "love" to do more TV work, and that he had been in talks, but that nothing had been confirmed.
"I'm not taking it too seriously because I had a fairly good life before Big Brother," he said.
Paul, from Reading, Berkshire, was a freelance car designer before entering the house with nine other contestants at the end of May.