(CNN) -- Leonard Nimoy isn't letting a health battle stop him from enjoying his life.
The "Star Trek" actor recently revealed on Twitter that he's been diagnosed with COPD, or chronic lung disease. (The COPD stands for chronic obstructive pulmonary disease.)
"I quit smoking 30 years ago. Not soon enough. I have COPD. Grandpa says, quit now!!" Nimoy, 82, tweeted. "Smokers, please understand. If you quit after you're diagnosed with lung damage, it's too late. Grandpa says learn my lesson. Quit now."
His admission prompted fans to express their concern for the actor, who's lately stayed busy with appearances on TV shows like "Fringe" and "The Big Bang Theory," plus popping up at the movies in "Star Trek Into Darkness."
But for everyone worried, Nimoy has assured them that he's hanging in there.
"I'm doing OK. Just can't walk distances. Love my life, family, friends and followers," he tweeted. "Just taped my comments for Star Trek Fest to be aired on EPIX Feb. 16th. Still enjoying my life."