Sean Penn, born to actor and director Leo Penn and actress Eileen Ryan, has two siblings: older brother, Michael Penn, and younger brother, Chris Penn.

Sadly, his younger sibling, Chris, who was also an actor, passed away untimely at the age of 40 on January 24, 2006.

He was reportedly found dead in his bed at his Santa Monica home on Ocean Avenue.

Sean Penn's Brother Chris Died of Heart Disease

As per Los Angeles County coroner's office [via the Los Angeles Times], Chris died of a deadly heart condition.

Investigators found that Chris died of "nonspecific cardiomyopathy," a heart muscle disease that is usually fatal over time. Additionally, coroner's spokesman Craig Harvey stated that his heart was enlarged, weak, and "could have given out at any time."

Meanwhile, the investigators also found that the actor was regularly taking multiple medications, which probably contributed to his death.

The results specifically highlighted one prescription medication — Phenergan, a commonly prescribed cough syrup that contains an antihistamine but is not widely considered dangerous in adults, according to doctors.

Harvey, however, noted the cough syrup, which also has codeine in it, played a role in Chris' death but was "not a direct cause."

Sean Penn Spoke on His Brother's Death

Sean eventually opened up about his brother's death for the first time in public during an interview with Larry King in September 2006.

He frankly stated that the "weight" was the problem. He said, "I mean, it was a natural death. But a natural death that was brought on by some hard living, but particularly weight."

Rightly so, Chris reportedly weighed 300 lbs. at the time of his death.

Sean further admitted that he and Chris were "very close," almost like best friends. Hence, he felt like he had lost a part of him when his brother passed away.

Sean Penn with his brother Chris Penn in 1985.

Sean Penn with Chris Penn in 1985. (Photo: Twitter)

"It's a piece of you. I'm one of three, so I'm either my right, left arm or the center at various times, and each was the other, so I intermittently have lost my right arm, the left or in the center, but that's life and people go through that," he said of losing a sibling.

That was not all. He also had high praise for Chris' acting abilities.

For him, Chris' performance in the 1997 crime drama film The Funeral always inspired him, making him realize his brother "was a size of talent."

A Look at Chris Penn's Work

Chris, born on October 10, 1965, was renowned as a skilled character actor from a prominent acting dynasty, who often played tough characters.

For instance, he would be cast as a villain, a working-class thug, or in a comic role.

He starred in films such as The Wild Life, Reservoir Dogs, The Funeral, Rush Hour, and True Romance.

Chris had started acting at the age of 12 at the Loft Studio and made his film debut in 1979's Charlie and the Talking Buzzard, starring Christopher Hanks.