R2 made it into the hall of fame last year. Now C3PO is being honoured along with four other androids for their contribution to robot history.
The ceremony will take place in October at the US's Carnegie Mellon University.
Honda's Asimo bot, Shakey the Robot, Astroboy and Robby the Robot are also getting inducted this year. They were selected by a panel of experts.
"The jury discussed this year's candidates at length and has made some excellent choices," said the founder of the Robot Hall Of Fame.
Important
"I'm happy to see some older, historically important robots like Shakey and Robby joining the newer ones like Asimo and C3PO."
Robots from both science and science fiction can be nominated for the honour.
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