Arnold Schwarzenegger's son shared a sweet tribute to his dad on the actor's 72nd birthday.

Baena, 21, shared a picture of him and his "Terminator" star dad pumping iron to wish him a happy birthday.

In the post on Tuesday, the former California governor was shown pointing to his son in approval, as he worked out at Gold's Gym, the same place where his father trained during his storied bodybuilding career.

"BIG happy birthday to the best training partner in the world! Love you dad," Baena captioned the photo.

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Baena is Schwarzenegger's son with Mildred Baena, his former housekeeper. Mildred and the Austrian actor had an extramarital affair together. Schwarzenegger and his ex-wife Maria Shriver have four children together.

Baena has made a name for himself on social media after posting several tribute posts to his dad.

In one recent post, Baena made headlines for recreating his father’s iconic bodybuilding photo taken in 1975. Schwarzenegger posed for the photo after he won Mr. Olympia for the sixth straight time.

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In another picture, a chiseled and shirtless Baena proudly held his wrist and flexed his bicep in the same way his dad did in an advertisement for a German protein product back in 1967.

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Schwarzenegger's latest project is "Terminator: Dark Fate," which blasts into theaters in November. The film is a reunion for Schwarzenegger and previous "Terminator" star Linda Hamilton, who played Sarah Connor in the franchise's first two films.