Joseph Baena rocks tank top with an image of the bodybuilding competition named after his father Arnold Schwarzenegger

As Arnold Schwarzenegger's son Joseph Baena keeps getting older, he looks more and more like a younger version of his father when he was just starting out back in the Seventies and Eighties.

The 21-year-old, who is Arnold's 'love child' with former housekeeper Mildred Baena, was spotted leaving the gym in Venice on Thursday after a long workout.

The results of that workout clearly showed, as Joseph was literally busting out of his skimpy blue muscle shirt with his huge pecs, shoulders and biceps on full display in the California sunshine.

Pumped up: 21-year-old Joseph Baena, who is Arnold Schwarzenegger's child with former housekeeper Mildred Baena, was spotted leaving the gym in Venice on Thursday

Pumped up: 21-year-old Joseph Baena, who is Arnold Schwarzenegger's child with former housekeeper Mildred Baena, was spotted leaving the gym in Venice on Thursday

Funnily enough, the tank top Baena selected for the workout session in fact had his father's name on it.

Arranged in a circular motif, the muscle shirt featured the silhouette of a Greek-style male form flexing muscles, with the words 'Arnold Schwarzenegger Classic' written in white along the top.

Baena paired the shirt with simple grey gym shorts and his habitual Converse sneakers, and was carrying a black gym bag. 

The Pepperdine alum, who's been dating fellow graduate Nicky Dodaj since they were students at the university, is a gym regular, frequently posting about his workout sessions and progress on social media. 

Ode to dad: Joseph was literally busting out of his skimpy blue muscle shirt, which in fact had his father's name on it

Ode to dad: Joseph was literally busting out of his skimpy blue muscle shirt, which in fact had his father's name on it

The gym, however, isn't the only spot Joseph frequents to stay in shape. 

Earlier this month, he was spotted hiking Runyon Canyon with Dodaj.

While the revelation that Joseph is Arnold's illicit son ultimately led to Arnold's divorce from Maria Shriver, the pair appear to remain amicable, as just this week Schwarzenegger was seen smiling while on a lunch date with his daughter Christina and his ex-wife.  

Buff: The Pepperdine alum is a gym regular, frequently posting about his workout sessions and progress on social media

Buff: The Pepperdine alum is a gym regular, frequently posting about his workout sessions and progress on social media

Cute couple: Baena has been dating fellow Pepperdine graduate Nicky Dodaj since they were students at the university; here seen in June in Los Angeles

Cute couple: Baena has been dating fellow Pepperdine graduate Nicky Dodaj since they were students at the university; here seen in June in Los Angeles

Relations also seem friendly between Joseph and his father, as three weeks ago he posted a gym-set pic with Arnold in honor of the latter's 72nd birthday.

While Arnold is making a big show of returning to acting and movie-making after his days as governor of California, his son Joseph has thus far not shown any interest in following in those particular footsteps.

As for Arnold, his latest grand return to the Terminator franchise hits theaters this November, and the film, titled Terminator: Dark Fate, will also feature his T2: Judgement Day co-stars Linda Hamilton and Edward Furlong. 

Like father like son: Relations seem friendly between Joseph and his father, as three weeks ago he posted a gym-set pic with Arnold in honor of the latter's 72nd birthday

Like father like son: Relations seem friendly between Joseph and his father, as three weeks ago he posted a gym-set pic with Arnold in honor of the latter's 72nd birthday

The prodigal mother returns: Arnold is making his grand return to the Terminator franchise this November, in the film Terminator: Dark Fate which will feature his T2: Judgment Day co-star Linda Hamilton

The prodigal mother returns: Arnold is making his grand return to the Terminator franchise this November, in the film Terminator: Dark Fate which will feature his T2: Judgment Day co-star Linda Hamilton

Joseph Baena is a spitting image of his dad Arnold Schwarzenegger as he shows off his arms in Venice

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