As Hollywood continues to reel from shock of the sudden death of former child star Aaron Carter on Saturday, tributes have been pouring out from the musician's fellow former Disney stars.

"For Aaron," Carter's ex-girlfriend and Lizzie McGuire star Hilary Duff wrote in an emotional tribute shared to Instagram. The two dated briefly in the early 2000s when Carter appeared as himself in a special holiday episode of the Duff-led Disney Channel show.

"I'm deeply sorry that life was so hard for you and that you had to struggle in front of the whole world. You had a charm that was absolutely effervescent...boy did my teenage self love you deeply. Sending love to your family at this time. Rest easy."

Carter spent the majority of his life in the spotlight—the younger brother of Backstreet Boys' Nick Carter, the I Want Candy singer released his own studio album at only nine years old. Struggling with his mental health under the constant scrutiny of the public eye, Carter was open about his battles with addiction and had shared that he was five years sober just months before his death.

"My heart goes out to his family and may he rest in peace," fellow Disney alum Lindsay Lohan told Entertainment Tonight. Lohan and Carter briefly dated shortly after he and Duff parted ways.

"And God bless him...and yeah, just [a] lot of love there," Lohan added.

Related: Aaron Carter, Rapper and Actor, Dies at 34

Raven-Symone Says Tragedy Should Be a Mental Health Wake-Up Call: 'Maybe One Day People Will Get the Hint'

aaron carter
CBS Media Ventures

Another star who's all too familiar with the scorching spotlight of child stardom, That's So Raven and Cheetah Girls actress Raven-Symone, told ET that Carter's untimely death should be a wake-up call to take mental health seriously.

"We're sending our love out to the family. We crossed circles multiple times within the music industry. My heart goes out to Nick [Carter]. It's such a tragedy.

I think we really do need to get the world in order, so we can start focusing on mental health. It's a real thing, and we need to stop losing our youth to it. Maybe one day people will get the hint," the actress said.

Carter was open about his mental health struggles; the star had been diagnosed with multiple personality disorder, schizophrenia, anxiety, and bipolar disorder. Ultimately, the Raven's Home actress says it's important to make mental health conversations a part of every day life.

"It's just a part of our everyday life to have check-ups, mentally, and help our society out," she added.

Carter is survived by his 11-month-old son Prince. He was 34 years old.