The 82-year-old actor had quit smoking 30 years ago, but that could not save him from being inflicted with Chronic Obstructive Pulmonary Disease( a non-reversible lung disease), reported Daily Mirror.
"I quit smoking 30 years ago. Not soon enough. I have COPD. Grandpa says, quit now!!," Nimoy tweeted.
The disease often caused by smoking, gets worse over time, as it leads to breathlessness, persistent coughing and frequent chest infections.
Nimoy, who announced his retirement from playing Spock in 2010, worked in and also made appearances in hit series like 'Fringe', 'The Big Bang Theory', 'Letters of Transit' and 'Brave New World' among others.