The Transformers remains one of the most beloved cartoons of the 80s and features some of the most iconic voice acting around. The series doubled as a half-hour commercial for the epic toy line and portrayed a war on Earth involving colossal robots capable of transforming into various vehicles and objects. Giant robots causing mayhem are always going to be a hit with kids. However, it was the masterful voice acting that helped elevate the material to something special.

Peter Cullen’s portrayal of Autobot leader Optimus Prime, both paternal and noble, resonated so much with 80s kids that he remained the voice of the character in the live-action Transformers films. Meanwhile, the current voice of Scooby-Doo (and the originator of Fred Jones) Frank Welker, breathed life into the Decepticon ruler Megatron. However, alongside them were several classic film and TV stars that helped make the franchise iconic.

A sci-fi icon joins the Transformers franchise.

In 1986 the animated series jumped to the big screen with The Transformers: The Movie. Perhaps most notable of the stars assembled was Mr. Spock himself, Leonard Nimoy. The Star Trek icon voiced the new Decepticon leader, Galvatron. Nimoy clearly had a blast lending his voice to the villainous character, infusing him with a raspy and sinister aura.

However, Nimoy’s contribution to the Transformers franchise extended beyond his portrayal of Galvatron in Transformers: The Movie. In 2011’s Transformers: Dark of the Moon, Nimoy once again provided his voice for a Transformer character. This time bringing life to the role of Sentinel Prime, Optimus Prime’s mentor that has become an adversary.

In The Transformers: The Movie, the cast also included the esteemed actor Robert Stack. Of course, he is widely recognized by 80s and 90s kids as the host of Unsolved Mysteries. Stack, a veteran actor who also starred in the classic TV show The Untouchables, lent his authoritative, deep voice to the would-be new leader of the Autobots, Ultra Magnus. Stack went on to embrace voice acting. He eventually appeared in other iconic animated shows such as King of the Hill and Recess.

Perhaps the most surprising talent to provide a voice to the original Transformers cartoon is none other than Orson Welles. The star and director of the esteemed Citizen Kane breathed his booming deep voice to the planet-sized Transformer called Unicron. Also introduced in The Transformers; The Movie, Unicron was the ultimate threat. He was a robot that feasted on and destroyed entire worlds. With his commanding voice, the character of Unicron exuded a sense of grandeur and menace that truly brought the larger-than-life villain to life.