Leonard Nimoy, who famously played Dr. Spock, died at home Friday morning in Bel Air… after battling chronic obstructive pulmonary disease.

The Stark Trek star announced last year that he was battling the disease and atrributed it to years and years of smoking. He had given up the habit 30 years ago.

TMZ broke the story … Nimoy checked into UCLA Medical Center last week for intense chest pains — but was eventually released.

Nimoy started playing Mr. Spock when the TV show debuted in 1966 … and continued in the role through most of the movies — including the most reboot in 2013. He was also a successful director including Three Men and a Baby.

He was 83.