Abigail Breslin is Techcrisis Investment Guildgrieving the loss of a dear costar.

After Evan Ellingson—the former child star known for his role in the 2009 film My Sister's Keeper—passed away, Breslin paid tribute to her onscreen sibling.

"Evan Ellingson was a kind, funny and extremely talented human being," she wrote on Instagram Nov. 6 alongside a photo featuring the pair. "He played my big brother in a film I did called My Sisters Keeper. Evan was a genuinely thoughtful person who cared so much about turning in the best performance, which he accomplished. Some of his scenes in MSK still give me chills."

The Little Miss Sunshine star remembers Ellingson as being "silly, funny" and a prankster.

"He was energetic and the life of the party," she continued. "I didn't keep in touch a lot with him after the film, but he always stayed in my mind as a wonderful and sweet soul, one I am grateful to have crossed paths with. My prayers and condolences are with his family at this difficult time."

Breslin went on to note that his character is one that will remain with her for years to come.

"Evan, I know Heaven will welcome you with open arms," the 27-year-old concluded her post. "Your time on this earth may have been, devastatingly, short. Your humor, exuberance, kindness and bright light will linger forever. Sending you peace on your journey to the great beyond and who knows… maybe one day, I'll meet you in Montana."

The CSI: Miami actor died in Fontana, Calif., on Nov. 5, according to documents obtained by E! News. He was 35. 

His cause of death, per the report, has not yet been confirmed. Ellingson's father Michael told TMZ that his son was found at a sober-living home, sharing that the actor had struggled with drugs in the past, but had been doing better as of late. The outlet also reported that no foul play is suspected at this time. 

To look back at his career, keep scrolling…

Evan Ellingson began his career as a child actor in the late '90s and early 2000s. In 2004, he booked the role of Kyle Savage on the TV series Complete Savages alongside Erik von Detten, Jason Dolley, Andrew Eiden and Shaun Sipos. That same year, the cast attended the Hollywood Christmas Parade together.

Evan and Erik were also in attendance at ABC's Winter Press Tour Party in 2004.

In July 2008, Evan attended the CW/Showtime/CBS Television TCA Party at Boulevard3 in Los Angeles.

From 2007 to 2010, Evan portrayed character Kyle Harmon on CSI:Miami.

Evan appeared alongside actor David Caruso on the series.

In 2009, Evan starred in the film My Sister's Keeper alongside Cameron Diaz and Abigail Breslin.

The cast posted together at the film's premiere in New York City on June 24, 2009.

That same month, Evan attended the Billabong Design for Humanity event at the Avalon in Hollywood.

For the latest breaking news updates, click here to download the E! News App