Kenny Baker, the British actor who starred as plucky robot R2-D2 in the "Star Wars" movies, died on Saturday at the age of 81, his agent and relatives said.

"Kenny Baker has sadly passed away and was found on Saturday morning by his nephew Drew, who was also his carer in the latter part of his life," his agent Johnny Mans said in a statement to AFP.

He said he had been ill for some time, adding: "Kenny was truly a great friend, one of the nicest guys you could ever wish to meet and a fabulous and talented performer."

Baker's nephew, Drew Myerscough, told local media his uncle had suffered respiratory problems for almost a decade.

Baker, who measured just one metre tall (three foot, eight inches), played the resourceful droid known for his whistles and beeps in 1977's "Star Wars" and in the five following movies.

Mark Hamill, who played Luke Skywalker in the first three films, paid tribute to a "lifelong loyal friend".

"I loved his optimism & determination. He WAS the droid I was looking for!" he wrote on Twitter, posting old black and white photos of them together.

20th Century Fox posted a photograph of Baker's character and his on-screen sidekick C3PO, saying: "Rest in peace, Kenny Baker, the heart and soul of R2-D2."

A wheelchair-bound Baker attended the European premiere in London of last year's "Star Wars: The Force Awakens", in which he received a mention in the credits.

"Unfortunately he was too ill to be part of the new Star Wars films," his niece Abigail Shield told Sky News television. "But he was consulted by certain people."

- 'Loved throughout the world' -She had earlier told The Guardian newspaper: "He brought lots of happiness to people and we'll be celebrating the fact that he was well loved throughout the world.

"We're all very proud of what he achieved in his lifetime."

British actor Ewan McGregor, who starred in the three Star Wars prequels, wrote on Twitter: "So sorry to hear about this. It was lovely working with Kenny."

The latest instalment of the franchise, "Rogue One: A Star Wars Story", is due out in December.

According to his official website, Kenny was born in Birmingham on August 24, 1934. He began performing at the age of 16 with a troupe called "Burton Lester's Midgets".

As well as "Star Wars", he starred in cult movies from the 1980s such as "Time Bandits" and "Flash Gordon".