Pell, 78, the most senior Catholic official worldwide to be jailed for child sex offences, is currently serving a six-year sentence handed down in March.
Catholic cardinal George Pell will have one last chance to overturn his conviction for sexually assaulting two teenaged choirboys after the Australian High Court on Wednesday agreed to hear the former Vatican treasurer's appeal.
Pell, 78, the most senior Catholic official worldwide to be jailed for child sex offences, is currently serving a six-year sentence handed down in March. He is not eligible for parole until 2022, when he will be 81.
The High Court hearing, to be presided over by a full bench of five or seven judges, will be held in March 2020 at the earliest, a court spokesman said. Pell will remain in prison until the appeal is heard.
Lawyers for Pell declined to comment on Wednesday's decision, which is the cardinal's final avenue to clear his name after an earlier appeal upheld his conviction by a lower court.
Prosecutors also declined to comment.
The lawyer for Pell's accuser, whose identity has been protected, said her client respected the appeals process despite the ups and downs he had been through.
"So we will be respectfully waiting for the outcome, but we do understand the anguish a lot of people in the community are feeling," lawyer Vivian Waller told Australian Broadcasting Corp.
The cardinal was found guilty in the Victorian County Court in December of abusing two 13-year-old boys at St Patrick's Cathedral in the late 1990s when he was archbishop of Melbourne. A first appeal was heard by the Victoria Court of Appeal, where judges upheld his conviction in a 2-1 majority in August.
The Australian Catholic church lamented the case dragging on due to the High Court ruling.
"This will prolong what has been a lengthy and difficult process, but we can only hope that the appeal will be heard as soon as reasonably possible and that the High Court's judgement will bring clarity and a resolution for all," Archbishop Mark Coleridge, head of the Australian Catholic Bishops Conference, said in a statement.
The High Court on Wednesday ordered Pell's lawyers to file their arguments for appeal by January 8, with the crown prosecutors' response due on February 5.
Pell's lawyers took the case to the High Court on the basis the Court of Appeal was wrong to have found that the jury's verdict was not unreasonable. Lawyers also argued the majority judges had erred in shifting the burden of proof to the defense to show that it would have been impossible for Pell to have committed the offenses.
Prosecutors said in their filing to the High Court last month there were no grounds for the appeal. They argued that the majority of the Court of Appeal made no error in their approach to evaluating the facts of the case and that the proposed appeal raised "no question of law of public importance".
High Court cases are decided by a majority.
Legal experts said the move by two judges of the High Court to refer Pell's bid to appeal to the full bench was unusual. Effectively the bid to appeal and the actual appeal will be heard together.
The outcome is very hard to predict, said Ben Mathews, a law professor at Queensland University of Technology, who had expected the court to refuse to hear the appeal.
"It's a really tricky one. The fundamental question is really whether the court decides it was open to the jury to reach the guilty verdict," Mathews said.
Pell was relieved of his position as Vatican treasurer after he was convicted, but remains a cardinal. The Pope has declined to comment on the case until the appeals process is exhausted.
For Pell to be dismissed from the priesthood, the Vatican's Congregation for the Doctrine of the Faith would have to find him guilty following a separate canonical trial or a shorter process.