Michelle Trachtenberg was poised for a major public comeback before her untimely death aged 39

Jennifer Hutchins, producer of the star's final film, 'Spyral', has now confirmed the actress was scheduled to attend a benefit screening of the documentary at the South by Southwest festival in Austin, Texas, on 12 March.

She told TMZ: "The team was aware of Michelle's health struggles, but she still planned to attend, either in person or via Zoom."

The New York City Medical Examiner's Office stated Michelle's family had objected to an autopsy, resulting in her cause of death being ruled "undetermined'.

Authorities have indicated that her death is not being treated as suspicious.

The SXSW event, now set to honour Michelle's memory, was intended to support mental health charities, including the National Alliance on Mental Illness.

'Spyral', directed by Bill Guttentag, features Michelle narrating diary entries of Michelle Cody White, who suffered from undiagnosed bipolar depression prior to her death.

The film's release was delayed due to the COVID-19 pandemic, with filmmakers seeking wide distribution.

Michelle began her acting career at the age of three and gained prominence with roles in 'Harriet the Spy' and 'EuroTrip'.

Despite her early success, she had stepped back from Hollywood in recent years.

A friend said: "She really pulled back from Hollywood in the last eight years."

Another source noted Michelle had been "really, really down emotionally" and had "told friends she was struggling" over the past year.

Tributes have poured in from friends and co-stars since her death, with Sarah Michelle Gellar, who portrayed her on-screen sister in 'Buffy the Vampire Slayer', sharing a heartfelt message in which she paraphrased a speech from the series.

Princess Eugenie, also a long-time friend of the actress, described Michelle as "thoughtful, generous and funny". Blake Lively and other 'Gossip Girl' co-stars also expressed their condolences.