By JENNA SLOAN
Fleeing into the Tube station, Carolyn Owlett felt her heart racing with panic. Behind the ticket barrier, a man she did not know was yelling her name, shouting that he loved her and that he wanted to be with her.
Hurtling on to the safety of a train, the mum-of-one was soon to discover she was at the start of a nightmare brought on by a rogue user of a social networking site.
Carolyn, 26, said: "I was terrified. This man was shouting my name and personal information about me across Oxford Circus station but I had no idea who he was.
"He said he'd come from Belgium to be with me. I was so scared. I yelled at him to leave me alone. He looked like he'd been shot through the heart."
Carolyn was to discover that a 21-year-old woman in Belgium had stolen her identity on Facebook.
She had set up an email and Facebook account in her name, grabbed 2,000 pictures from the net, doctored some of them and conned Carolyn's friends and family into becoming her "friend".
The fake Carolyn, using pictures and details of the real one, had been in a 17-month cyber affair with Regis Remacle - the man at the Tube station - and had even claimed to be the mother of Carolyn's son Billy, three.
The story started to unravel last week after lovestruck Regis travelled from Brussels to declare his feelings to Carolyn in person.
Carolyn - who has a boyfriend - said: "I eventually discovered my Facebook account, and those of my friends and family, had been plundered and that a Belgian woman was pretending to be me.
"She claimed to be the mother of my son and even had cybersex with men online.
"The whole incident has been very upsetting."
Carolyn, from east London, is a radio and TV producer and presenter. In 2004 she was part of girl group The 411 who had two top five singles in the chart. She said: "I had a great time as part of the group and a few fans set up tribute sites online.
"It was flattering that they enjoyed our music and I sometimes went on the forums to chat.
"The group split in 2005 and I had my son Billy in 2007 with my ex. As a new mum I found Facebook invaluable for catching up with friends and staying in touch with my parents, who live abroad."
Carolyn, one of 26million Brits to use the site, said: "I had no problems until June this year, when I received an odd message from a stranger called Regis.
"It said 'Does your boyfriend know what you've been up to?' I thought it was a case of mistaken identity, so I sent the guy a message back to say so.
"I also started getting messages from men in Africa and Turkey calling me 'sugar lips' or 'hot stuff'.
"Then last week I was walking to Oxford Circus Tube. I was aware of someone walking very close, then I heard 'Carolyn' whispered in my ear. I realised it was the man following me."
Carolyn ran through the station, leaving the stranger shouting after her. He turned out to be Regis, 28, a graphic designer.
On the train Carolyn recalled the odd message from months earlier. She said: "As soon as I got off the train I found him on Facebook and my boyfriend messaged him, asking what was going on. He replied within seconds and the story came out."
Regis believed he had been conducting a steamy virtual affair with Carolyn for 17 months. He had seen thousands of pictures of her friends and family and knew where she worked.
He'd had text and online sex with 'Carolyn', chatted to her on Skype and had bought her a diamond necklace.
Carolyn explained: "Regis sent me dozens of emails showing our supposed conversations. I felt sick and violated.
"My boyfriend was with me and we have a great relationship so he believed me when I told him the affair was fiction. But if we hadn't been so strong this could have destroyed us. She'd trawled the internet for more than 2,000 pictures of me and had badgered my pals, family and work contacts to be 'friends'.
"I do feel sorry for Regis, as for the past 17 months he's been living a lie through no fault of his own."
The pair discovered the stalker was a 21-year-old Belgian woman calling herself Kristella Erbicella.
Following the Tube snub, Regis contacted the fake Carolyn and Erbicella responded with a confession. Regis then shared that message with Carolyn.
Carolyn contacted her pals and discovered Erbicella had asked every single one to be her Facebook "friend", saying she was a mate of Carolyn's. Several believed her and accepted the request, giving her access to Carolyn's pictures and information.
Carolyn said: "Erbicella said she had been a fan of The 411. When she was feeling down one day she decided to use my picture and set up a Facebook page. She got compliments and it made her feel good, so she carried on.
"She had to find out more and more about me to keep the pretence going and the whole thing spiralled out of control."
She used one of Carolyn posing with a girl pal and replaced the friend with Regis, shown above, showing how they would look as a couple. Carolyn said: "I couldn't believe my eyes. It looks like Regis and I are a happy couple but in reality we'd never even met. It's scary to see what Erbicella was capable of."
In the one message Erbicella sent to Carolyn, she wrote in broken English: "I want to apologise for everything I've done.
"I really respect you. You have always been my idol. I'm sorry for everything, I do not want have problems with you.
"It is hard for me as I love someone who does not know I exist as me. I just want you to understand me and what I feel right now."
Carolyn said: "This woman has harassed my friends and used photos of my son. She even set up an online photo album dedicated to Billy - who knows what kind of people have seen those photos?
"I communicate with Billy's nursery through email and dread to think what could have happened. She could have turned up at the gates and taken him.
"The experience has shown me that nothing you post on the internet ever goes away. People should be careful when posting pictures of their kids and their lives.
"I found out the hard way that you never know who is watching."