UPDATED 11.40PM: Actor Leonard Nimoy, who won a worldwide fan base as the pointy-eared half-human, half-Vulcan Mr Spock in the blockbuster "Star Trek" television and film franchise, has died at the age of 83.

His wife, Susan Bay Nimoy, confirmed his death to the New York Times yesterday.

Nimoy had been suffering from chronic obstructive pulmonary disease.

The US space agency NASA joined Leonard Nimoy's Star Trek co-stars to bid adieu to the veteran actor.

"I loved him like a brother. We will all miss his humour, his talent, and his capacity to love," William Shatner, who played Captain James Kirk against Nimoy's Mr Spock on Star Trek, said on Twitter and Facebook.

"RIP Leonard Nimoy. So many of us at NASA were inspired by Star Trek. Boldly go ..." echoed the space agency on Twitter, under a photo of the Star Trek cast visiting the space shuttle Enterprise in 1976.

"To boldly go where no man has gone before" was a catchphrase from the opening credits of the original Star Trek TV episodes.

George Takei, 77, who played the helmsman of the Starship Enterprise on Star Trek, told CNN how he and Nimoy had been good friends for half a century.

"When discussing a scene, he had a remarkable talent for analysing the scene very quickly, in terms of its point, its drive," Takei recalled.

"But he was also able to guide other actors. He was really a company actor ... A real leader and a brilliant actor."

Zachary Quinto, who played Spock in the two most recent Star Trek films, said he was heartbroken by the actor's passing.

"I love you profoundly, my dear friend, and I will miss you everyday," he said on Instagram, alongside a portrait of Nimoy.

"May flights of angels sing thee to thy rest," added the 37-year-old actor.

"Leonard, you lived long and prospered, and were an inspiration to me and to millions. Rest in peace," tweeted Canadian astronaut Chris Hadfield.

Barack Obama has also paid tribute, lauding his portrayal of the logical Mr Spock as well as his contributions to the arts and sciences.

"Long before being nerdy was cool, there was Leonard Nimoy," the US President said in a statement after the actor's death at his Los Angeles home at age 83.

The US president praised the Boston-born star as a "lifelong lover of the arts and humanities, a supporter of the sciences, generous with his talent and his time".

"And of course, Leonard was Spock - cool, logical, big-eared and level-headed, the centre of Star Trek's optimistic, inclusive vision of humanity's future," he said.
"I loved Spock."

Obama recounted meeting Nimoy in 2007 and said it was "only logical to greet him with the Vulcan salute, the universal sign for 'Live long and prosper'."

"After 83 years on this planet - and on his visits to many others - it's clear Leonard Nimoy did just that," Obama said, adding he and his wife Michelle joined fans in mourning for the actor.