Star Trek star Leonard Nimoy - famous for playing Spock on the sci-fi show - has revealed that he is suffering from lung disease.

The 82-year-old actor told his Twitter followers that he had given up smoking 30 years ago, but that it was "not soon enough".

He said: "I quit smoking 30 years ago. Not soon enough.

"I have COPD. Grandpa says, quit now!!"

Referring to his Star Trek catchphrase Live Long and Prosper, he ended his message: "LLAP."

COPD stands for chronic obstructive pulmonary disease and is the name for a collection of lung diseases, including chronic bronchitis, emphysema and chronic obstructive airways disease.

People with COPD have difficulty breathing and it is often linked to smoking.

Last week the actor was seen being pushed in a wheelchair and using an oxygen cylinder.

Leonard enjoyed a cameo role in last year's Star Trek film, Star Trek Into Darkness. He also played Dr William Bell on the TV series Fringe until 2012.