Mickey Rooney Jr., Original Mouseketeer and Son of Mickey Rooney, Dead at 77

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Mickey Rooney Jr., the first child of Mickey Rooney and an original Mouseketeer, has died at the age of 77.

His longtime companion Chrissie Brown confirmed that he died Saturday in his Glendale, Arizona home but the cause of death is unknown, per The Hollywood Reporter.

The musician and actor, "peacefully passed away," according to a Facebook post from Rooney Jr.'s long-time friend, actor Paul Peterson. The two worked together as original Mouseketeers at Disney.

"I first met Mickey, the oldest of nine siblings sired by his famous father, when he and Timmy were hired by Disney to be Mouseketeers in 1955. Mickey Junior was tall and talented. He could sing, dance and act…and get in trouble," he wrote, adding the rebellious trio was fired for 'Conduct Unbecoming a Mouse.' "

Peterson continued, "Mickey Junior was the personification of 'damaged goods.'  He gave all he could."

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"I was born on the same day as Mickey's father and 'The Mic' gave me, unsolicited mind you, the most useful advice I ever got. It is one of my greatest sorrows that he didn't do the same for his son. Mickey Rooney Junior. Rest In Peace at last. We will see to your wishes," he endearingly concluded the post.

Rooney Jr. played in bands with Willie Nelson, as well as acted alongside him in 80s films Honeysuckle Rose and Songwriter. Additionally, he appeared in and scored the soundtrack of John Brahm's Hot Rods to Hell. He also earned a role in the 1975 NBC movie Beyond the Bermuda Triangle.

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Born in Birmingham, Alabama with the name Joseph Yule III, he and his brother Tim Rooney were hired as backup cast members on ABC's The Mickey Mouse Club in 1955. They participated in a variety of episodes before both were fired.

Rooney Jr. was an incredibly talented musician, who played guitar, keyboard, bass, drums and harmonica. In the 1960s, he recorded multiple songs, including "The Wandering Wind," "The Choice Is Yours" and "It Certainly Ain't a Nice Thing." He was also involved in a band with brothers Tim and Teddy, and even appeared on the ABC musical series Shindig!.