Taylor Swift has been banned from using evidence from a profiling expert in her groping case against a Colorado DJ.

The pop superstar is preparing to face off with David Mueller in court after he filed suit in September, 2015 claiming he lost his job at Denver radio station KYGO because Swift falsely accused him of groping her and lifting up her skirt while backstage at a 2013 concert. He is seeking $3 million (£2.3 million) in damages.

The Shake It Off singer responded with a countersuit accusing him of sexual assault and battery, and a trial date has been set for next month (Aug17).

In the lead up to the court showdown, lawyers for both parties have been challenging pieces of evidence submitted for the case, and on Friday (21Jul17), Mueller won a motion seeking to strike testimony from Dr. Lorraine Bayard de Volo, a professor of women and gender studies at the University of Colorado-Boulder.

According to TheWrap.com, Dr. Bayard de Volo had been prepared to tell the court Mueller fit the profile of a person who could be motivated to commit sexual harassment or assault.

In his ruling, U.S. federal judge William J. Martinez declared the witness' opinion "creates a very substantial risk of prejudice against Plaintiff (Mueller) and of confusing the issues at trial".

She will, however, still be allowed to give evidence regarding other aspects of Swift's case.

The news emerges a day after the judge agreed to allow Swift's legal representatives to question Mueller over key evidence he lost on damaged electronic devices.

The missing evidence included a two-hour audio recording of a conversation Mueller had with his boss Robert Call the day before he was fired in June, 2013. Snippets had already been handed over to his attorney, but the original material is no longer available for the trial.