American Amanda Knox made a brief appearance in an Italian court as she began a bid to overturn her conviction for the murder of Meredith Kercher.
Knox, 23, was jailed last year for 26 years for the killing in Perugia in 2007. Her former boyfriend Raffaele Sollecito was jailed for 25 years.
The hearing lasted just 15 minutes and the case was adjourned until 11 December.
Miss Kercher, 21, from Coulsdon, south London, was found with her throat cut.
The Leeds University student's semi-naked body was found partially covered by a duvet in her bedroom in the house she shared in the Italian city.
Italian Sollecito was convicted after a trial heard how he held down Miss Kercher while Knox attacked her with a knife.
The trial heard the pair had cornered Miss Kercher after starting a sex game with Ivorian drug dealer Rudy Guede, who was jailed for 30 years for the killing, although that was reduced to 16 years on appeal.
The BBC's Duncan Kennedy, who is in Perugia, says the case was adjourned because one of the lawyers is five months pregnant and has been advised not to travel to the court from Rome.
Knox's defence team maintains that the DNA evidence in the case was inconclusive and has argued it may have been contaminated when analysed.
It particularly focuses on disputed traces of DNA found on the knife the prosecution said was used in the murder, and on the clasp of Miss Kercher's bra.
In their appeal motion, defence lawyers were sharply critical of the verdict, maintaining it was based on mere hypotheses and saying that the motive was absent.
Knox's parents, from Seattle, have said they are hopeful their daughter will be released once judges in Italy have re-examined the evidence.
However, if her conviction is upheld, her sentence could be increased.
Her father Curt told BBC Radio 4's Today programme he was "cautiously optimistic" that his daughter would be cleared.
"The main factor of the appeal is really going to be the forensic evidence," he said. "There's not one speck of Amanda - no hair, no saliva, no blood, nothing - anywhere in the room where Meredith lost her life.
"Amanda was portrayed as somebody that she absolutely is not. She is 180 degrees different from the evil person she was portrayed as."
The result of the appeal is not likely to come before the new year.
As in the original trial, the verdict will be decided by the judge, a fellow magistrate and six jurors.