The super buff apple doesn't fall far from the insanely muscular tree.
Arnold Schwarzenegger shared a heartfelt message with his son, Joseph Baena, on his 20th birthday, alongside a snapshot of one of their father-son workouts.
"Happy birthday Joseph! You’re a fantastic son and a great training partner," the Terminator star captioned the beaming gym pic, which he posted to Instagram on Monday.
"You get stronger and smarter every year and I’m so proud of you," he continued. "I love you."
WATCH: Arnold Schwarzenegger's Son Joseph Baena Looks So Much Like Him -- See the Pic!
The 70-year-old action star and body builder had his impressive biceps on display in a green T-shirt as he proudly pointed at his lookalike son, who was working his chest and arms on a weight machine.
Last week, Schwarzenegger celebrated his son Christopher's 20th birthday with a heartwarming throwback photo from when his son was a toddler.
"Happy birthday Christopher! You're a wonderful student, a hilarious and kind soul, and a fantastic son. I'm so proud of you, I love you, and I can't wait to see what's next," he wrote.
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Christopher is the star's youngest child with ex-wife Maria Shriver, with whom he also shares daughters Katherine, 26, and Christiana, 25, and son Patrick, 23. Schwarzenegger and Shriver ended their relationship in 2011 after news broke that he had fathered Joseph 14 years earlierwith the family's housekeeper, Mildred Baena.
However, Schwarzenegger has been very involved in Joseph's life, and the pair have been training and body building partners for several years.
For his 19th birthday last year, the former California governor took his son to Munich, Germany, to celebrate Oktoberfest. Check out the video below for a look at the fun birthday vacay.