Former child star Adam Rich died in January due to the "effects of fentanyl," according to a report from the Los Angeles Medical Examiner's office.

The actor, who was best known for his role on the hit ABC comedy-drama "Eight Is Enough," was found dead at the age of 54 in his Los Angeles home on Jan. 8. Rich's manner of death was cited as an "accident," per the report. 

Rich was eight-years-old when he was cast as Nicholas Bradford in "Eight Is Enough." He played the youngest son of widower Tom Bradford's eight children in the television series, which ran for five seasons from 1977 to 1981. Rich was dubbed "America's Little Brother" during his time on the show.

"Eight is Enough" also starred Dick Van Patten, Diana Hyland, Betty Buckley, Grant Goodeve, Lani O'Grady, Laurie Walters, Susan Richardson, Dianne Kay, Connie Newton and Willie Aames.

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In addition to "Eight Is Enough," Rich's other television credits included "Dungeons & Dragons," "Baywatch," "Small Wonder," "Gun Shy," "Code Red" and "CHiPs." He reprised his role as Nicolas in the TV spin-off movies 1987's "Eight Is Enough: A Family Reunion" and 1989's "An Eight Is Enough Wedding,"

In recent years, Rich had stayed away from working in front of the camera. He last appeared as himself in the 2003 film "Dickie Roberts: Former Child Star" and played Crocodile Dundee in a 2003 episode of "Reel Comedy."

Over the course of his life, Rich was arrested for attempted burglary as well as driving under the influence.

Rich's death was announced by his representative Danny Deraney in an emotional statement that he shared on Twitter.

"Adam was simply a wonderful guy. He was kind, generous and a warrior in the fight against mental illness," Deraney wrote. 

"Adam did not have an ounce of ego. He was unselfish and always looked out for those he cared about. Which is why many people who grew up with him feel a part of their childhood gone, and sad today," he continued."He really was America's Little Brother."

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Deraney thanked the public "for reaching out," before also noting, "If you knew Adam, you just loved the guy. And oh the stories he could tell."

After Rich's death, Aames, who played his older brother Tommy in "Eight Is Enough," shared a tribute to his late co-star on Facebook.

"This morning [my wife] Winnie woke me with the heartbreaking news of Adam Rich's passing," Aames wrote in a January post. "I'm gutted. Adam was more than a colleague. He was very much my only little brother. A lifelong friend."

He continued, "These last few years Adam had dreams of renewing his career. He was one of those kid actors that our generation will always remember."

Buckley, who played Rich's stepmother Abby in "Eight Is Enough." posted a slideshow of photos featuring the late actor with herself and the show's cast on Instagram.

"Adam Rich was a light and my young pal for the four seasons I was blessed to work with him on 'Eight Is Enough,'" she wrote. "I adored him and loved working with him in our scenes together on the show. He was so sweet, funny, fresh and natural. He brought a lot of joy to all of us on the show and to our audiences.

She continued, "Adam and I have remained friends all of these years. His love and support have always meant a lot to me. I am shocked by the news I received this morning of his death. Sending my love and deepest condolences to his friends and family. In recent years Adam dedicated himself to providing inspiration for others with mental and emotional illness. I will miss him greatly."