Sean Penn Ripped Man Smoking

8/12/2013 7:15 AM PDT

Sean Penn -- Ripped Man Smoking

More than THREE DECADES after he went topless in "Fast Times at Ridgemont High," Sean Penn struck a Spicoli pose in Spain ... and proved he's more JACKED than ever.

The 52-year-old actor exposed his ripped physique while smokin' a cigarette in Ibiza, Spain this weekend during a vacation with model Cristina Piaget -- but this post ain't about her.

Check out this pic of Sean back in 1982 -- when he was 21 years old -- and then make a decision.