Spain's Princess Cristina arrives at court with her husband Inaki Urdangarin to attend trial in Palma de Mallorca, Spain, March 2, 2016. [Photo/Agencies]

MADRID - Spanish Princess Cristina, the youngest sister of King Felipe VI of Spain and sixth in line to the Spanish throne, on Thursday testified in a tax fraud case in which she is one of the defendants.

Cristina is the first member of the Spanish Royal family to have to answer criminal charges and is one of 17 defendants in the case, which is related to the Noos Institute founded by her husband Inaki Urdangarin and his partner, Diego Torres. She could face a maximum sentence of eight years in jail if she is found guilty.

Noos is suspected to have fraudulently obtained over 6 million euros of public funds (around 6.6 million US dollars), some of which were siphoned off through the company Aizoon, in which Cristina and Urdangarin were joint shareholders.

Cristina, who is employed by Spanish bank La Caixa, said she had "no" specialist accounting knowledge and said she had a 50 percent holdings in Aizoon because "my husband asked me to and I said yes."

She testified she had not asked Urdangarin about Aizoon's activities because "it wasn't interesting and our children were little," but added she did not believe Aizoon had been set up to siphon off money from tax authorities.

She also denied having any bank account in tax havens, saying that although she has an account in Switzerland, it is because she lives there.

Earlier in the day, Urdangarin testified that former King of Spain, Juan Carlos I, Cristina's former private secretary Carlos Garcia Revenga and her elder sister Elena, knew of his business dealings.