He's so vein: Sean Penn, 52, shows off his bulging biceps as he goes shirtless on the daily jog

PUBLISHED: 20:45 EST, 5 November 2012 | UPDATED: 21:07 EST, 5 November 2012

For his latest movie role in Gangster Squad he played a lean and mean looking Mickey Cohen.

But Sean Penn must be preparing for a very different kind of character as he was spotted looking significantly more bulked up on his daily run in Malibu on Monday.

The 52-year-old ‘Milk’ actor was sporting long-hair and a bare-chest and had veins bulging out of his arms as he walked along the road.

Tough guy: Sean Penn looked like he had gained a lot of muscle as he walked bare-chested in Malibu today

Penn is often seen running around his Malibu beach home, and this time he was accompanied by fellow actor Henry Hopper.

Hopper, 22, is the son of the late actor Dennis Hopper who became friends with Penn after the pair co-starred in the 1998 cop movie, Colors.

In July, Henry was accused of plying a 15-year-old girl with drugs and alcohol and raping the teenager according to a lawsuit filed by the girl's mother.

Good friends: Penn was running with Henry Hopper, son of his late friend actor Dennis Hopper

Role model: Sean Penn appears to have taken the troubled youth under his wing

Helping out a friend: Dennis Hopper and Sean Penn were co-stars and friends

Penn, who has two children of his own, daughter Dylan Frances, 13 and son Hopper Jack, 9, seems to have taken the troubled youth under his wing in the absence of his father.

Attempts to reach Henry Hopper for comment were unsuccessful.

Since divorcing wife Robin Wright in 2010, Penn has been linked to everyone from supermodels Petra Nemcova and Jessica White to Scarlett Johansson, but he is currently single.

Henry's mother, Katherine LaNasa, was the fourth wife of Dennis Hopper, who was married five times during his lifetime and had three other children, daughters Marin, Ruthanna and Galen.

It was revealed in September that Hopper’s nine-year-old daughter Galen had inherited almost $3million for his fortune.

The actor was in the middle of an acrimonious divorce from his fifth wife Victoria Duffy when he died in 2010.

Although a pre-nuptial agreement ensured Duffy received nothing in his will, their daughter Galen was left $2.85 million in cash along with $600,000 worth of property.