LOS ANGELES - The stars of Star Trek tweeted their well wishes to co-star Leonard Nimoy who is receiving treatment in hospital for severe chest pains.
The actor best known for playing Mr Spock, was taken to UCLA Medical Centre in Los Angeles on Feb 19, TMZ said.
Nimoy, 82, announced last year that he has chronic obstructive pulmonary disease.
William Shatner, who helmed the USS Enterprise as Captain Kirk, said he was "uplifted by the show of love & caring" for his friend.
I am uplifted by the show of love & caring tweeted to my dear friend @TheRealNimoy. I join the chorus of well wishers for a quick recovery!
— William Shatner (@WilliamShatner) February 23, 2015
George Takei, who played Hikaru Sulu, asked his followers on Twitter to join him in wishing Nimoy "a speedy recovery".
My friend and Star Trek colleague Leonard Nimoy (@TheRealNimoy) was hospitalized with chest pains. Join me in wishing him a speedy recovery.
— George Takei (@GeorgeTakei) February 24, 2015
He also posted his well wishes on Facebook.
Fans have responded, expressing their concern while referencing the long-running sci-fi series.
A photo posted by Lee Sargent (@leesargent) onFeb 24, 2015 at 12:43am PST
Comments such as "Live long and prosper", a catchphrase popularised by Nimoy, have proliferated online.
— DAVID (@intenseCA) February 25, 2015
Nimoy last appeared in JJ Abrahm's remake of Star Trek, as Spock Prime, an older Spock who lives in an alternate reality. Spock in the remake is played by Zachary Quinto.