The 27-year-old, who will join Paris Saint-Germain from Chelsea after the World Cup, turned down the chance to play for Portugal during his days at Benfica.
"The blood running through my veins is green and yellow," he replied, according to his father Ladislau. "My heart is Brazilian and I will only play for my country."
"Being a father watching your son playing for Brazil makes my dreams come true," Ladislau continues. "This is the moment when everyone is united, people forget about the rivalries and are together for the same reason."
Brazil take on Colombia in the quarter-finals on Friday night (kick-off 9pm), with a semi-final against either Germany or France up for grabs.
Hit play on the video below to watch more of David Luiz's dad (he must have got his hair from his mum's side).
