Leonard Nimoy says he has developed chronic obstructive pulmonary disease.
The Star Trek actor wrote on Twitter that despite having quit smoking 30 years ago, it was "not soon enough." His advice to his Twitter followers? "Grandpa says, quit now!!"
Nimoy, 82, also wrote that he is "doing OK. Just can't walk long distances."
His last on-screen appearance was in 2013 in Star Trek Into Darkness, in which he reprised his role as Mr. Spock, the Vulcan character he has played since 1966.