(CNN) Kenny Baker, the British actor best known as R2-D2 in the "Star Wars" films, has died at the age of 81, according to his niece, Abigail Shield.

Baker was being looked after by Shield's brother, who found him Saturday morning. Shield said Baker had been ill for years with a lung condition.

She also said her uncle -- who was 3 feet, 8 inches tall -- did not expect to "live past his teenage years because he was a 'little person,' so it is pretty amazing he lived this long."

Baker died in his sleep Saturday morning, according to his nephew and caregiver Andrew Myerscough.

That was Baker's wish -- to go peacefully, his nephew said. "I couldn't ask for more."

Up until his final moments, Baker was in good spirits and was watching the Olympics on television, Myerscough said.

But the actor's family had watched him deteriorate for years because of respiratory problems.

"I cared for him every day," Myerscough said. "He was a huge part of my life and I'm going to miss him."

"He was an inspiration to many people -- he never let his disability affect or stop him from doing anything he wanted to do."

Baker was best known for the robot character he first played in 1977's original "Star Wars."

"I have had a fairly quiet year, and when the sunshine has allowed I have enjoyed the peace and tranquility of my garden," Baker wrote on his website.

He was fondly remembered on social media Saturday.

Screenwriter Brian Lynch tweeted: "Rest in Peace, Kenny Baker. Thanks for bringing my favorite STAR WARS character (and 1st STAR WARS figure) to life."

British actor Rahul Kohli said in a post: "You brought life to one of my favourite characters, thank you Kenny Baker. Rest in peace."