Boston Dynamics has drawn huge attention with viral videos of its humanoid and dog-like robots

Japan's SoftBank Group will sell an 80 percent stake in robotics firm Boston Dynamics to Hyundai, the trio said Friday, in a deal that values the US company at $1.1 billion.

Boston Dynamics has drawn huge attention with viral videos of its humanoid and dog-like robots, whose uncanny movements and impressive tricks have helped stoke fears that androids could one day become a threat to humans.

The engineering firm was founded in 1992 and bought in 2013 by Google, which sold the company on to SoftBank three years ago.

The Japanese conglomerate will keep a 20 percent stake through one of its affiliates and will work with South Korea's Hyundai to "propel development and commercialisation of advanced robots", the companies said.

The financial terms of the deal were not disclosed. It is expected to close by June 2021, the statement said.

Boston Dynamics has won attention for creations like Atlas, a that can run on different types of surfaces and perform backflips, and Spot, its first commercial —a nimble four-legged machine that moves like a dog and went on sale in the summer.

The firm's chairman Marc Raibert told AFP in 2019 that the fascination and fear sparked by such life-like robots was not "realistic".

"There's (a) fear, which is more a science-fiction that the robots are going to be so smart that they'll be angry with us. I don't think it's realistic in today's robots," he said.