The father-son pair were spotted enjoying a bike ride in Venice, California on Wednesday. Schwarzenegger, 68, and Baena, 18, were all smiles as they rode their own two-wheelers in their casual T-shirts and shorts.
They were seen outside Gold’s Gym where they often work out together.
Joseph is the son of Mildred Baena, Schwarzenegger’s former housekeeper who he had an affair with when married to ex-wife Maria Shriver.
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The actor also has four children with Shriver: Katherine, 26, Christina, 24, Patrick, 22, and Christopher, 18.