Speaking for his first time on the subject, he told the French edition of Elle magazine that four-year-old Augustin is an important member of his family.
He also said he has always 'recognised' the boy as his own and that his three-year-old daughter Valentina treats him like a brother.
Mr Pinault, 49, has a close relationship with his daughter by actress wife Salma Hayek, who was born 11 months after Augustin.
But he is currently embroiled in a bitter legal battle over how much money he should pay to his son with his former lover, and it has been claimed she took legal action after failing to reach a settlement out of court.
Read more: http://www.dailymail.co.uk/tvshowbiz/article-2036693/Salma-Hayeks-husband-Francois-Henri-Pinault-secret-son-Linda-Evangelista.html#ixzz1mSjwteAm