More than 250 potential jurors were warned Monday that they would have to give up four months of their lives to serve on the murder trial of the Upper West Side nanny accused of killing two small children in 2012.

The prospective panelists weren’t told which case they were being considered for.

“It is a murder case, a high-profile case,” Manhattan Criminal Court Judge Gregory Carro said. “I want you to think hard and deep on whether you’ll be able to serve on this jury.”

Former nanny Yoselyn Ortega, 56, is accused of killing Lucia Krim, 6, and her brother, Leo Krim, 2, because of petty grievances against their mother. Jury selection is scheduled to continue for at least another week.