"Glee" star Cory Monteith surprised fans this week when it was abruptly announced that he had voluntarily entered rehab for substance abuse -- some 11 years after Monteith says he first checked into a treatment facility, at age 19. And while the 30-year-old's addiction issues may seem inconsistent with his squeaky-clean image, celebrities spending time in rehab is hardly a new trend.

From Robert Downey Jr. to Lindsay Lohan, Britney Spears to Catherine Zeta-Jones, check out these other famous faces who have been admitted to rehabilitation centers.

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  • Lindsay Lohan

    The troubled 26-year-old was sentenced to<a href="http://www.huffingtonpost.com/2013/03/18/lindsay-lohan-plea-deal_n_2902620.html" target="_hplink"> 90 days of mandatory rehab </a>after pleading no contest to reckless driving and lying to police following a June 2012 car accident. The rehab visit, which starts May 2, 2013, will be Lohan's sixth time in a treatment facility.

  • LeAnn Rimes

    The country crooner <a href="http://www.people.com/people/article/0,,20625497,00.html" target="_hplink">checked herself into a rehabilitation center</a> for stress and anxiety in August 2012.

  • Matthew Perry

    The former "Friends" star was admitted into rehab in 1991 and 2001 for addiction to prescription painkillers and alcoholism. Ten years later, Perry entered treatment again as a preventive measure. "I'm making plans to go away for a month to focus on my sobriety and to continue my life in recovery," <a href="http://www.tmz.com/2011/05/12/matthew-perry-treatment-center-rehab-substance-abuse-friend-prescription-pills/" target="_hplink">he told TMZ at the time</a>.

  • Cory Monteith

    The "Glee" star surprised everybody when he<a href="http://www.huffingtonpost.com/2013/03/31/cory-monteith-rehab_n_2990315.html" target="_hplink"> voluntarily checked himself into a treatment facility</a> for substance abuse in April 2013. The 30-year-old has said he first entered rehab at age 19.

  • Catherine Zeta-Jones

    In April 2011, the "Chicago" actress checked into rehab to treat bipolar disorder.

  • Demi Moore

    Demi Moore <a href="http://www.thedailybeast.com/articles/2012/07/17/demi-moore-s-downward-spiral-since-her-split-from-ashton-kutcher.html" target="_hplink">checked into rehab</a> in spring 2012 after a disastrous fallout from ex-husband Ashton Kutcher and hospitalization after allegedly inhaling nitrous oxide, or whip-its.

  • Kim Richards

    "Real Housewives of Beverly Hills" star Kim Richards' battle with alcohol has been well-documented on the show. In December 2012, <a href="http://abcnews.go.com/blogs/entertainment/2012/01/housewives-kyle-richards-reveals-what-sent-kim-to-rehab/" target="_hplink">she checked into rehab again</a>.

  • Robert Downey Jr.

    After years of struggling with cocaine and heroin addiction and serving jail time, the actor is clean and sober.

  • Amy Winehouse

    Singer Amy Winehouse was found dead in her London home on July 23, 2011. The 27-year-old singer's life was cut short due to accidental alcohol poisoning. <em>CORRECTION: In an earlier version of this slideshow, the date Ms. Winehouse died was incorrect. She died on July 23, 2011.</em>

  • Mike "The Situation" Sorrentino

    It came as little surprise to viewers of MTV's "The Jersey Shore" that star partier Mike "The Situation" Sorrentino <a href="http://www.huffingtonpost.com/2012/03/21/the-situation-rehab-mike-sorrentino-responds_n_1371330.html" target="_hplink">checked into rehab</a> in March 2012. The reality star said on his Facebook page that he was seeking treatment for<a href="http://www.huffingtonpost.com/2012/03/21/the-situation-rehab-mike-sorrentino-responds_n_1371330.html" target="_hplink"> medication used to treat exhaustion</a>.

  • Demi Lovato

    The "X Factor" judge has talked openly about going in and out of rehab when she was in her teens for eating disorders and mental health issues. "Treatment was so difficult at first, I remember walking around saying 'I'm in prison!' They needed to have strict rules for me to understand how sick I was," <a href="http://www.okmagazine.com/news/demi-lovato-rehab-was-prison-i-needed-get-help" target="_hplink">she said</a>.

  • Gerard Butler

    The gruff Scottish actor revealed in a <a href="http://www.mensjournal.com/magazine/cover-story-excerpt-gerard-butlers-wild-ride-20121019" target="_hplink">2012 article with "Men's Journal"</a> that he hadn't touched a drink in 15 years. "I think, on a basic level, I have a pretty addictive personality. Both good and bad," he said.

  • Charlie Sheen

    In February 2011 Charlie Sheen claimed he was clean of drugs and alcohol, but high on himself. The actor has publicly struggled with addiction for years, but many doubt his claims of sobriety.

  • Britney Spears

    America's reigning pop princess <a href="http://www.people.com/people/article/0,,20012207_20012337,00.html" target="_hplink">checked into rehab in February 2012</a> amid a public meltdown that included a now-infamous head-shaving incident and the temporary loss of custody of her two boys.

  • Drew Barrymore

    Drew was famously an addict as a child. By her own admission she said she had her first drink at 9, began smoking marijuana at 10 and began using cocaine at 12. By age 13 she entered rehab and has maintained her sobriety since.

  • Robin Williams

    The comedian overcame a cocaine addiction, but headed back to rehab after 20 years of sobriety in 2006 to address his issues with alcohol.

  • Fergie

    The Black Eyed Peas singer kicked a crystal meth and ecstasy habit.

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