Arnold Schwarzenegger was a gushing, proud dad on Wednesday as he wished his son Joseph Baena happy birthday on Instagram.
"Happy birthday Joseph! Watching you graduate from college this year and seeing you follow your passions has been amazing," he captioned a series of father-son snapshots, including one of them working out. "You are a fantastic son, and I can't wait for our next training session. I love you."
The newly-anointed 22-year-old who Arnold fathered with the family's housekeeper, responded, "Thank you dad! Love you too and can't wait for the next pump."
Arnold's birthday message comes less than a week after wishing his son Christopher a happy 22nd birthday, as well.
"Happy birthday Christopher, you are such a jewel," he wrote alongside three images. "I have loved every minute of watching you grow up, you make me so proud every day and I can't wait to see what you become. I love you!"
Arnold has five children, but the four children he shares with his ex Maria Shriver — Katherine, 29, Christina, 28, Patrick, 26, and Christopher — have little to no relationship with Joseph, who Arnold acknowledged as his son in 2011. Since then, the "Terminator" actor has become very close with Joseph, often posting images of him on social media.
Earlier this year, Arnold beamed while attending Joseph's college graduation.
"Congratulations Joseph! Four years of hard work studying business at Pepperdine and today is your big day!," he wrote on Instagram. "You have earned all of the celebration and I'm so proud of you. I love you!"