They have also begun circulating pictures on the internet showing her looking dishevelled and posing topless. Miss Yeater has claimed that Bieber, a devout Christian, confessed to being a virgin before having sex with her in a toilet after a show at the Staples Centre in Los Angeles on October 25 last year.
The former clerk claims Bieber is now ignoring her pleas to support her three-month-old son Tristyn Anthony.
Canadian Bieber, who is currently dating actress Selena Gomez, 19, has tweeted that he wants to "ignore the rumours and focus on what is real". His representatives have branded Miss Yeater's lawsuit "malicious, defamatory and demonstrably false".
However, her lawyers said they have 'credible' evidence and will fight until Bieber agrees to a DNA test.