Veteran actor Peter Spellos -- who starred on the TV series "American Dreams" and an animated 'Transformers' series -- is dead after battling pancreatic cancer ... TMZ has learned.

Peter died early Sunday morning while he was at Franciscan Hospice House in Indianapolis ... according to his friend and acting student, Jennifer Smith.

Jennifer, who has power of attorney for Peter, tells us he'd been receiving care at the facility as his health deteriorated, and she adds ... "He was loved and cared for and surrounded by people during his final days."

Peter was perhaps best known for voicing the character Sky-Byte on the "Transformers: Robots in Disguise" cartoon series. He played the role for 39 episodes, and it made him a big hit on the comic-con circuit.

Besides his extensive voice work ... Peter was also a live actor in movies and TV. He played Motorman in "Men in Black II" and Gus in the NBC show "American Dreams."

His brother, James Spellos, says Peter will be cremated, and the family is planning an online gathering for fans.

He was 69.