The husband of Spain's Princess Cristina is testifying for a third day in the tax-and-embezzlement trial in which he, the princess and 15 others are accused.

Inaki Urdangarin's testimony Thursday will be followed by that of another defendant before Cristina, who faces two charges of tax fraud, testifies.

The case centers on accusations that Urdangarin used his former title of Duke of Palma to embezzle about 6 million euros ($6.6 million) in public contracts through a non-profit institute he co-ran.

Urdangarin , who faces a possible sentence of 20 years, told the court Wednesday that palace officials oversaw the princess' tax dealings and were aware of his business operations.

Cristina, sister of King Felipe VI, is the first Spanish royal to face criminal charges since the monarchy's 1975 restoration.