'Star Trek' legend Leonard Nimoy has been diagnosed with a serious lung disease.

The actor - who played Spock in the sci-fi series - is suffering from Chronic obstructive pulmonary disease (COPD), despite giving up smoking 30 years ago.

leonard nimoy

Leonard Nimoy

Revealing his illness on Twitter, he wrote: "I quit smoking 30 yrs ago. Not soon enough. I have COPD. Grandpa says, quit now!! LLAP."

The disease is actually a collection of lung complaints, including chronic bronchitis, emphysema and chronic obstructive, which make it extremely difficult for the sufferer to breathe.

leonard nimoy

Leonard as Spock in 'Star Trek'

Leonard had a cameo in the most recent Star Trek film 'Into Darkness' as Spock Prime last year.

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  • Jonathan Frakes (Commander William T. Riker)

  • Jonathan Frakes (Commander William T. Riker)

    In addition to serving nobly as "Number One" for seven seasons and four films, Frakes also went behind the camera, helming "First Contact" and "Insurrection" as well as several episodes of "TNG" and "DS9." He also directed "Clockstoppers," "Thunderbirds," and the "Librarian" TV movies starring Noah Wyle. He continues to direct for TV: recent credits include "Burn Notice," "Castle," and "Leverage."

  • William Shatner (Captain James T. Kirk)

  • William Shatner (Captain James T. Kirk)

    Shatner reprised his role as James Tiberius Kirk in seven "Star Trek" feature films and was (sob) killed off in 1994's "Star Trek: Generations." Now 82, Shatner has continued acting, racking up two Emmys for his role as Denny Crane on "Boston Legal." Most recently, he starred on the CBS series "$h*! My Dad Says" and those "The Negotiator" Priceline ads. In 2011, he directed "The Captains," in which he interviewed the other actors who've played captains in the Trek franchise.

  • Leonard Nimoy (Spock)

  • Leonard Nimoy (Spock)

    When Spock heroically sacrificed himself in 1982's "Wrath of Khan," fans reeled. Nimoy, now 82, has had a love/hate relationship with his iconic role as the highly logical half Vulcan, writing a biography in 1975 entitled "I Am Not Spock," followed 20 years later by "I Am Spock." However, he's come to terms with his sci-fi legend status, appearing as "Spock Prime" in Abrams's 2009 reboot. He also played the mysterious William Bell on "Fringe" and voiced "Action Figure Spock" on a 2012 episode of "The Big Bang Theory."

  • DeForest Kelley (Dr. Leonard "Bones" McCoy)

    Kelley played the cranky but indispensable doctor known for declaring, "He's dead, Jim," and insisting, "I'm a doctor, not a (fill in the blank)." He played Bones on the big screen in six "Star Trek" films but was so identified with his role that he had trouble lining up other work. He became a regular at "Star Trek" conventions until his death in 1999 from stomach cancer.

  • James Doohan (Montgomery "Scotty" Scott)

    Where would the Enterprise be without its trusty chief engineer, who frequently pushed the craft past its limits, despite telling the captain, "She can't take much more." Doohan played Scotty in seven "Star Trek" films, inspiring several fans to become engineers themselves. He died in 2005 of pneumonia, and after his death, some of his ashes were launched into space and the rest scattered near his home in Washington state.

  • Nichelle Nichols (Lt. Nyota Uhura)

  • Nichelle Nichols (Lt. Nyota Uhura)

    Nichols, now 80, considered leaving the series until Martin Luther King, Jr. encouraged her to stay on. Her groundbreaking role as the always capable communications officer inspired generations of black actors, including future "TNG" star Whoopi Goldberg. After "Star Trek," Nichols helped recruit minorities for NASA, wrote an autobiography and appeared on "Heroes" and the comedies "Are We There Yet?" and "Snow Dogs."

  • George Takei (Lt. Hikaru Sulu)

  • George Takei (Lt. Hikaru Sulu)

    Takei played the intrepid helmsman in six "Trek" feature films and one episode of "Star Trek" Voyager." Since coming out in 2005, Takei has been a proud proponent of LGBT rights. When he married his longtime boyfriend in 2008, Nichelle Nichols was his matron of honor and Walter Koenig his best man. The actor's post-"Trek" career includes roles on "Heroes," "The Simpsons," and Nickelodeon's "Supah Ninjas." He's been called "the funniest guy on Facebook," where he has more than 4 million followers.

  • Walter Koenig (Pavel Chekov)

  • Walter Koenig (Pavel Chekov)

    Boyish Koenig was added to the series in its second season because of his resemblance to Monkee Davy Jones (and not because the Russians complained about a lack of cosmonauts). The Russian navigator became a regular and a fan favorite. Besides numerous Trek-related projects, he had a recurring role as villainous Bestor on the '90s sci-fi series "Babylon 5." He also taught acting at UCLA. He's currently working on a post-apocalyptic graphic novel about vampires.

  • Ricardo Montalban (Khan Noonien Singh)

    The most memorable villain in the franchise's history first appeared in a 1967 episode and was brought back as Kirk's nemesis for "Star Trek II: The Wrath of Khan." (That impressive chest on then-62-year-old Montalban was all his own, by the way.) In between, Montalban played the mysterious Mr. Roarke on "Fantasy Island." He appeared as the grandfather in the "Spy Kids" films, one of his last roles before his death in 2009. The Ricardo Montalban Theatre was dedicated in 2004 in Los Angeles.

  • Majel Barrett (Nurse Christine Chapel)

    Barrett wasn't just Nurse Chapel, she was also the voice of the computer and, as any fan knows, Mrs. Roddenberry. In the 1979 feature film, she was promoted to "Dr. Chapel" and reprised that role in "Star Trek IV: The Voyage Home." She later appeared in "The Next Generation" as Deanna Troi's mother who had a thing for Picard. Barrett died in 2008 of leukemia, but her voice appeared in the 2009 Abrams film as Queen Robot.

  • Mark Lenard (Sarek)

    Lenard first played Spock's father, a Vulcan ambassador, in the 1967 episode "Journey to Babel," having previously played a Romulan commander in a 1966 episode. He appeared in "Star Trek: The Motion Picture," not as Sarek, but as a Klingon Captain. He returned as Sarek in "The Search for Spock," "The Voyage Home" and "The Undiscovered Country." He died in 1996 at the age of 72.

  • Patrick Stewart (Captain Jean-Luc Picard)

  • Patrick Stewart (Captain Jean-Luc Picard)

    The Shakespearean actor, now 72, has "made it so" since 1987, when "The Next Generation" debuted. He's captained the Enterprise in "Star Trek: Generations," "First Contact," "Insurrection," and "Nemesis," as well appeared in the "Deep Space Nine" pilot. He's also Professor X in the "X-Men" films, a role he'll reprise in the upcoming "X-Men: Days of Future Past" in which he'll (presumably) meet his younger self, played by James McAvoy.

  • LeVar Burton (Lt. Comdr. Geordi La Forge)

  • LeVar Burton (Lt. Comdr. Geordi La Forge)

    Burton is one of the few actors in the franchise who will always be best known for a non "Trek" role, that of Kunta Kinte in "Roots." To generations of kids, he's also the beloved host of "Reading Rainbow." He directed episodes of "Voyager," "DS9," and "Enterprise," and hosted and produced the documentary "The Science of Peace." Since "Trek," he's continued to act, appearing as Martin Luther King, Jr. in "Ali" and as himself on "Community" and "The Big Bang Theory."

  • Michael Dorn (Worf)

  • Michael Dorn (Worf)

    Dorn played the gruff Klingon in 175 episodes of "TNG" and "DS9" and four films, which means he's racked up more screen time in character than anyone else in the franchise. Other roles include the Sandman in the two "Santa Clause" sequels, the President of the United States in a 2009 episode of "Heroes," and a recurring role on "Castle" as Dr. Burke, Kate Beckett's police psychiatrist. Fittingly, he also plays "Future Guy" in Dodge Dart commercials.

  • Gates McFadden (Dr. Beverly Crusher)

  • Gates McFadden (Dr. Beverly Crusher)

    McFadden's character was fired and replaced in the second season by Diana Muldaur, but rehired after the chemistry between Picard and the new character didn't pan out. She reprised her role in all four "TNG" movies and also voiced several games. Her non-Trek roles include the '90s series "Marker" with Richard Grieco, Paul Reiser's boss in "Mad About You," and a judge on "Franklin & Bash."

  • Marina Sirtis (Counselor Deanna Troi)

  • Marina Sirtis (Counselor Deanna Troi)

    The half-human, half-Betazoid character frequently wore cleavage-baring outfits, so Sirtis <a href="http://www.bbc.co.uk/cult/st/interviews/sirtis/page26.shtml" target="_blank">was delighted</a> to become a Starfleet officer and don a uniform. She also played Troi in four "Trek" films. In addition, she's appeared on "Earth: Final Conflict," "Stargate SG-1," "Without a Trace," and "Grey's Anatomy."

  • Brent Spiner (Data)

  • Brent Spiner (Data)

    Since playing the most personable android since C3PO, Spiner has never stopped acting: He played an Area 51 scientist in "Independence Day" and had roles in "The Aviator," "I Am Sam," and "Phenomenon." Other TV credits include "Warehouse 13," "Threshold" and the "Them, Robot" episode of "The Simpsons." In 2011, Spiner launched "Fresh Hell," a comic webseries in which he played a version of himself as a washed-up actor.

  • Wil Wheaton (Wesley Crusher)

  • Wil Wheaton (Wesley Crusher)

    It's not easy being a teenager in space, especially when so many fans hate you. Wheaton (who'll turn 41 this year) left acting temporarily after "TNG" ended. After attending acting school, he began voicing cartoons, video games, and audiobooks. He's appeared on episodes of "Leverage," "Eureka" and "The Big Bang Theory." Wheaton <a href="http://wilwheaton.net/" target="_blank">runs his own blog</a>, and used to write a column for The Onion's AV Club. His film credits include "Stand By Me," "Toy Soldiers" and "Flubber."

  • John de Lancie (Q)

  • John de Lancie (Q)

    First appearing as the quixotic Q on "TNG," de Lancie reprised the role on "DS9" and "Voyager." He went on to appear on "Stargate SG-1," "Andromeda," and "The Secret Circle" and the films "Crank: High Voltage" and "Gamer." He had an unforgettable arc on "Breaking Bad" as the air traffic controller father of Aaron Paul's girlfriend: After she dies of a drug overdose, his despair leads to a major airline crash, all results of Walter White's depraved indifference.

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