Peter Cullen’s cause of death revealed days after 'Transformers' voice actor died at 85

Peter Cullen, the legendary voice actor best known for voicing Optimus Prime in the Transformers franchise and Eeyore in Winnie the Pooh, died from cardiac arrest, according to his death certificate obtained by PEOPLE.

Cullen died on August 26, 2026, at his home in Los Angeles at the age of 85. His death was confirmed by his representative and family, who previously said that he passed away peacefully surrounded by his loved ones.

The death certificate lists cardiac arrest as the immediate cause of death. Respiratory arrest, cerebellar metastasis, hypoxia, chronic obstructive pulmonary disease, hypertension and hyperlipidemia were also listed as contributing conditions.

Cullen's family remembered him following his death and encouraged fans to honour his legacy by embracing compassion, service and kindness.

The Canadian-American actor became synonymous with Optimus Prime after first taking on the role in the original animated Transformers series in 1984. His deep, commanding voice helped define the Autobot leader and made the character one of the most recognisable figures in animation.

Cullen continued to voice Optimus Prime for decades, reprising the role across animated projects, video games and the live-action Transformers films. He returned as Optimus Prime for Michael Bay's 2007 Transformers movie and continued appearing in the film franchise, most recently voicing the character in 2023's Transformers: Rise of the Beasts.

Outside the Transformers franchise, Cullen was also widely recognised as the voice of Eeyore in Winnie the Pooh. He began voicing the gloomy but beloved donkey in 1988 and continued playing the character in various productions over the years.

Cullen's career extended well beyond his two most famous roles. He also lent his distinctive voice to numerous animated and television projects throughout a career spanning several decades.

Following news of his death, fans and fellow performers paid tribute to Cullen's contribution to animation and pop culture. His portrayal of Optimus Prime, in particular, became a defining part of the character's identity for generations of Transformers viewers.

Cullen is survived by his four children. His death marks the loss of one of the most recognisable voices in animation, with his work as Optimus Prime and Eeyore leaving a lasting legacy across film, television and popular culture.