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Despite the 12 years Enrique and Anna have spent together, Julio says he has yet to meet the retired Russian tennis player.
"You know I have to tell the truth, I have never met Anna," Julio told the Mirror. "Yes, my wife, and my kids and his brothers have, but I have never met her, no, no, never.
"My kids are very independent," he added, "It is difficult to see Enrique because he is all over the world."
Julio said that despite having not met 32-year-old Anna, he approved of his son's choice of partner.
"Anna is very beautiful," he said. "They have good taste my kids."
Anna and Enrique did not attend his brother's wedding in 2012.
Exclusive: Julio Iglesias Jr marries his model love Charisse Verhaert
Iglesias patriarch Julio proudly looked on as his son Julio Iglesias Jr wed Belgian model Charlise Verhaert in Spain, but Enrique and Anna couldn't be present due to scheduling conflicts.
Marriage rumours have long surrounded Enrique and Anna themselves although the couple have said they have no intention of tying the knot.
In May 2013 false claims were made that after more than a decade together, the pair were soon planning to say 'I do' in an extravagant Miami wedding ceremony.
"They're finally going to do it next week," an insider revealed to The Sun. "And have invited stars including Nicole Scherzinger, Lewis Hamilton, Jennifer Lopez, Eva Longoria and David Beckham and Victoria Beckham."