Madrid - Spain's Princess Cristina was scheduled to appear in court Saturday to answer a judge's questions in a corruption investigation involving her husband, Inaki Urdangarin.
Local media referred to it as another decisive day for the stability and future of the monarchy, which has come under increasing public scrutiny during the nation's economic crisis.
The princess, 48, was summoned to testify after an investigation into alleged tax evasion and money laundering implicated the royal couple, El Pais newspaper said.
It was expected to be the first time that a member of a Spanish monarchy appeared in court as the subject of a criminal case.
Neither she nor her husband have been charged, but Urdangarin and an associate have been accused of misappropriating millions of dollars worth of public funds through contracts with regional governments.
The princess has been out of the public eye for several months, relinquishing official ceremonial duties.
Part of the money in question was said to have ended up in a company that managed her royal household finances.