The “Terminator” tweeted a photo with his son, Joseph Baena, dressed in his cap and gown at his college graduation.
It says, “Congratulations Joseph! Four years of hard work studying business at Pepperdine and today is your big day! You have earned all of the celebration and I’m so proud of you. I love you!”
Schwarzenegger fathered Baena with his housekeeper during his long marriage to TV journalist Maria Shriver.
He told “60 Minutes” in 2012, “I inflicted tremendous pain on Maria and unbelievable pain” on their four children.
Schwarzenegger served as California governor from 2003 to 2011.