Rosie O'Donnell Says Harriet the Spy Costar Michelle Trachtenberg 'Struggled' Before Her Death: 'I Loved Her'

Rosie O’Donnell is mourning the loss of her Harriet the Spy co-star Michelle Trachtenberg.

Following the news of Trachtenberg’s passing at age 39 on Wednesday, Feb. 26, O’Donnell called it "heartbreaking" in a stateme.

"I loved her very much. She struggled the last few years. I wish I could have helped," O’Donnell, 62, shared.

O’Donnell and Trachtenberg starred together in 1996’s Harriet the Spy, which marked Trachtenberg’s big-screen debut at just 10 years old.

Another co-star, J. Smith-Cameron, also reflected on Trachtenberg’s passing. "I played Mrs. Welch, Harriet’s mother, in Harriet the Spy. Michelle had been on The Adventures of Pete & Pete, but this seemed to be her first lead film role. She was so excited," she recalled.

"Her natural ebullience was heightened by the excitement of it all. She was a very charming little girl," Smith-Cameron continued. "Years later, we reconnected briefly on social media, and she was always warm toward me. I feel very shocked and unsettled to hear of her passing."

The New York Police Department confirmed to PEOPLE that officers responded to a 911 call at 1 Columbus Place in New York City around 8 a.m. Wednesday.

"Upon arrival, officers observed a 39-year-old female unconscious and unresponsive. EMS responded to the location and pronounced the victim deceased," police stated, adding that "criminality is not suspected."

The investigation remains ongoing. The New York Post was the first to report her death.