The drama and English teacher was forced to leave her job at a London girls' school when her towel slipped and she exposed herself on the Channel 4 TV show in 2001.
Miss Ellis, known to millions of viewers as Penny, has left the spotlight and moved to East Sussex to be a supply teacher. Despite claiming in a recent magazine interview that she is happy with her new life, the 35-year-old has found it difficult to return to her former career.
She told Now magazine that after Big Brother she had become obsessed with money and fame but found the pressure of the celebrity circuit self-destructive.
A member of staff at Hillcrest school, Hastings, where Miss Ellis found work, said she had had "trouble fitting into school life. The children recognised her and it made a difference to her working relationship with the pupils".
On Big Brother, the six-foot blonde kissed a male contestant and said she was ready to have sex on TV to win the pound;70,000 prize.
The show's producers placed an apology on screen following the towel incident which triggered a ratings surge with about four million viewers tuning in.
When Miss Ellis became the first contestant to be voted off the show, Cauther Tooley, her then headteacher at Sarah Bonnell school, east London, demanded to see her about her "inappropriate" behaviour. Two weeks later she announced her decision to quit but not before she had posed naked again bar a few well-placed soap suds. The picture deal with Express Newspapers, which publishes the Daily Star and OK magazine, was reportedly worth pound;30,000.
Miss Ellis spent the following months going to celebrity parties and charity balls. She judged the 2001 Miss Ireland competition and starred in a celebrity edition of The Weakest Link.
Now that she is teaching again, Miss Ellis is trying to live a low-profile life on the south coast. A Hillcrest school spokeswoman said she was not currently working there. But Miss Ellis has not completely abandoned show business ways: her agent said she would do a phone interview with The TES - for pound;100. We declined.