The jury, which consists of seven women and five men, is due to begin hearing testimony tomorrow.
But Justice Simon Moore, who is presiding over the case, also spoke briefly to them yesterdaybefore sending them home.
He reminded the jurors of their obligations, including warning them not to speak to anyone outside their number about the trial.
They had to approach the task "absolutely dispassionately", he said, and put aside anything they had seen, read or heard about the case.
There had been a lot of material written and broadcast about Millane's death, Justice Moore said, but he added it was irrelevant and had "no bearing" on the trial or the jury's ultimate verdict.
"Anything you have seen or heard outside the courtroom has no place in your deliberations and you must consciously put those aside," he said.
"For you to adhere to the oath or affirmation you made... you have to keep an open mind."
The judge also reminded the 12 jurors that they must not undertake any inquiries of their own during the trial.
"From where you are sitting you literally have a grandstand seat, and it's the evidence in this court and nothing else, that you need to consider," he said.
"So for that reason you mustn't go out and search the internet - that's a judicial order, and the consequences for that are huge.
Justice Moore asked any prospective jurors who had attended any of the vigils to disclose it before the trial began.
The accused, who is represented by well-known Auckland lawyers Ian Brookie and Ron Mansfield, will continue to have interim name suppression throughout the trial - the reasons for which are also suppressed and cannot be reported by media.
The Crown Solicitor at Auckland Brian Dickey, along with former London barrister Robin McCoubrey, are prosecuting the case.
Millane's parents, David and Gillian, arrived in Auckland at the weekend and spent a day with the police and prosecution team as they prepared for the evidence they are likely to hear during the trial.
Detective Inspector Scott Beard and Detective Senior Sergeant Greg Brand were also in court yesterdayafter leading the police's efforts to find Millane.