Belfast-born salesman John Duffy's Cheryl Kerl has attracted over 41,000 fans and even prompted the release of a mock autobiography of the X Factor judge.
"I realised the whole appeal of Twitter was it attracts lots of celebrities," he told The Mirror. "I also realised I could write something a lot more interesting than, 'I'm at Pret A Manger eating a tuna sandwich'.
"I was tinkering on my laptop one night when, out of the blue, Cheryl Kerl popped into my head. It combined the celebrity appeal of Twitter plus my love of comedy writing."
He continued: "I didn't know much about the real Cheryl other than having watched a few X Factor shows, but I read up a bit on her and found writing in Geordie dialect came very easily - I have a Geordie mate and can mimic him to a tee."
Duffy, who now lives in Reading, told the paper that he began writing comedy 10 years ago.
"I loved it and found it flowed very naturally. I sent satirical one-liners to the Terry Wogan show on Radio 2. They liked them and began reading bits out almost daily. I would get up at 6am to get abreast of the news. It was unpaid but a learning curve."
The 53-year-old revealed the account had proven popular with other celebrities on the social networking website.
"Emma Freud asked, 'No-one has made me laugh as much as your tweets. Who the b*llocks are you?'. Bill Bailey, Alexander Armstrong, Ross Noble, Peter Serafinowicz and the DJs Sara Cox and Scott Mills are also fans. And from what I hear, Cheryl Cole has no complaints."
He added: "My wife Grace and my two sons are so proud. Seeing the book on the shelves at Waterstones was a real goosebumps moment."