Bill Cosby's lawyers have pressed a judge to keep the comedian's damaging deposition in a decade-old lawsuit out of his sexual assault trial, saying Cosby agreed to answer questions under oath after being assured he would not be charged with a crime.
The defence has insisted Cosby had an oral promise from the district attorney at the time that he would not be prosecuted over a 2005 sexual encounter with Andrea Constand, a former Temple University basketball manager.
The judge previously refused to dismiss the charges on those grounds, but is now being asked to disallow the deposition when the case goes to trial in June.
A new district attorney had Cosby arrested last year, after the deposition was unsealed and dozens of new accusers came forward.
Cosby, now 79 and blind, has said his encounter with Constand was consensual. He could get 10 years in prison if convicted. He is free on one million dollar bail.
The Cosby Show star once known as America's Dad smiled as he arrived at the suburban Philadelphia courthouse with his entourage.
Judge Steven O'Neill, who is hearing pretrial arguments, suggested that Cosby's decision to testify could have been strategic. He found no evidence that Cosby's lawyers tried to get the promise in writing before letting him testify.
They might have thought it was better for him to testify than plead the Fifth Amendment and have a civil jury think he had something to hide, the judge said.
Defence attorney Brian McMonagle said the judge would set a bad precedent if he let the testimony in.
"I don't want DAs making promises that they don't later keep," Mr McMonagle said. "That strikes at the heart of fundamental unfairness."
Cosby was questioned a decade ago as part of a lawsuit brought against him by Ms Constand. The long-married comedian testified about a series of affairs with young women and said he sometimes gave them pills or alcohol before sex. Ms Constand eventually settled in 2006 for an undisclosed sum.
The pretrial hearing is expected to last two days, with another hearing on the evidence set for December. The judge ordered a break Tuesday afternoon while the two sides tried to agree to some of the facts underlying their arguments.
The judge must also decide if 13 other accusers can testify against Cosby at the trial.
Cosby's lawyers want the judge to disallow such testimony about "prior bad acts", saying prosecutors are reaching back to the "casting couch" era to round up accusers and build a "stale" case.
The defence contends the women's memories have been compromised by time, age and widespread news coverage of the case.
"The fact that even the most fervently held memories can actually be tainted - or altogether false - is supported by a vast existing and growing body of science," Mr McMonagle wrote.