The information available confirms the specific casting of Orson Welles as the character Bumblebee is incorrect. According to production records, the voice of Bumblebee in the animated series Transformers was provided by actor Dan Gilvezan.

Orson Welles did, however, contribute a major voice performance to a Japanese-produced animated feature associated with the Transformers franchise. His sole credit in the realm of anime or Japanese-influenced animation is the role of Unicron in the 1986 animated film The Transformers: The Movie. This performance stands as a significant footnote in his career, as it was his final role before his death in 1985. He recorded his dialogue for the film on October 5, 1985, just five days before he passed away.

In The Transformers: The Movie, Welles provided the voice for Unicron, a massive, planet-sized Transformer who consumes entire worlds. Despite his legendary status as an actor and filmmaker, Welles reportedly held the role in low regard. He privately expressed dissatisfaction, describing the project as playing the voice of a toy from Japan involved in what he considered a simplistic narrative about outer space. Despite his personal misgivings, his distinctive, deep baritone voice gave the character a unique presence. Contemporary analysis notes that his dispassionate delivery made Unicron sound like a bored yet menacing god, and his performance has since become an appreciated part of the film's legacy.

Beyond this single anime-related role, Welles had an extensive and celebrated career as a voice actor in other media, most notably in radio and film narration. He was famous for his rich, authoritative speaking voice, which he used to great effect in his early radio work, including the infamous 1938 The War of the Worlds broadcast, and in film narration for his own movies such as The Magnificent Ambersons. However, his work on The Transformers: The Movie remains his only documented credit in the specific field of anime voice acting.