Undetected men in guesthouses, drop-ins at celebrity homes and swimming a mile to reach a star's property? Celebrities with stalking cases deal with some of the strangest things imaginable.

Nowadays, with the Internet to keep tabs on Hollywood, stalking might seem less serious than it is, but these celebs have had to come to terms with the scariest of stalkers. Celebrity stalkers put their victims through a lot, and luckily no serious repercussions have come to the stars in the slideshow below.

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  • Selena Gomez

    46-year-old <a href="http://www.huffingtonpost.com/2011/10/18/selena-gomez-granted-rest_n_1017544.html" target="_blank">Thomas Brodnicki began stalking then 19-year-old Selena Gomez in 2011</a>, and he allegedly told his shrink he was going to kill Gomez. According to TMZ, Brodnicki traveled from Chicago to LA to meet Selena and visited her workplace at least three times.

  • Mark Zuckerberg

    <a href="http://www.huffingtonpost.com/2011/02/07/pradeep-manukonda-mark-zuckerberg-stalker_n_819990.html" target="_blank">Mark Zuckerberg filed a restraining order against his stalker, Pradeep Manukonda</a>, in 2011 after he wrote the Facebook CEO handwritten letters and threatening Facebook messages. He also tried contacting Zuckerberg's sister and girlfriend and was reportedly seen outside Facebook headquarters and Zuckerberg's home. Manukonda said he was merely seeking advice from Zuckerberg <a href="http://www.tmz.com/2011/02/07/mark-zuckerberg-restraining-order-facebook-social-network-santa-clara-county-stalker-letters-priscilla-chan/" target="_blank">in an interview with TMZ</a> and that he did not mean to scare him. "I'm a peaceful guy ... I'm sorry he thought I was trying to harm him," said Manukonda. "I'll respect his privacy."

  • Jennifer Lopez

    In August 2013, <a href="http://www.huffingtonpost.com/2013/08/22/jennifer-lopez-stalker_n_3794467.html" target="_blank">a man broke into Lopez's Hamptons home and remained undetected in the guest house</a> for six days. J.Lo already <a href="http://www.tmz.com/2013/08/22/jennifer-lopez-hamptons-mansion-stalker-arrested/#ixzz2f56hGGiv" target="_blank">had a protective order against him</a> for contacting her mother earlier in the year.

  • Ashley Tisdale

    <a href="http://www.huffingtonpost.com/2013/06/01/ashley-tisdale-stalker-arrested_n_3372229.html" target="_blank">Ashley Tisdale filed a restraining order against Nicholas Fiore</a> after her sent her no fewer than 18,000 tweets, most of which can be described as "delusional" and "dangerous." The harassment, she felt, was putting her and her boyfriend in danger.

  • Jennifer Aniston

    In 2010, <a href="http://www.huffingtonpost.com/2010/07/20/jason-peyton-jennifer-ani_n_652955.html" target="_blank">Jason R. Peyton traveled cross-country in a delusional attempt to marry Jennifer Aniston</a>. Police found him with a sharp object, duct tape and love notes to the "Friends" star. Authorities said he was stopped after spending days trying to find Aniston on Sunset Boulevard.

  • Catherine Zeta-Jones

    Dawnette Knight, 35, <a href="http://news.bbc.co.uk/2/hi/uk_news/wales/4666313.stm" target="_blank">stalked and threatened Catherine Zeta-Jones multiple times between 2003 and 2004</a> after she claimed she was in love with Zeta-Jones' husband, Michael Douglas. In a letter Knight wrote to Douglas, she said she was "going to slice [Catherine Zeta-Jones] up like meat on a bone and feed her to the dogs."

  • Uma Thurman

    Jack Jordan, a 37-year-old pool cleaner and lifeguard, <a href="http://www.huffingtonpost.com/2008/05/06/jury-convicts-uma-thurman_n_100380.html" target="_blank">stalked the "Kill Bill" and "Pulp Fiction" star from 2005 to 2008</a>, with an intense high school crush. He showed up on Thurman's Greenwich Village doorstep and on the Manhattan set of her movie "My Super Ex-Girlfriend" and sent her bizarre cards and letters, at least 20 of them after he was committed to a Maryland mental facility.

  • Madonna

    <a href="http://www.huffingtonpost.com/2012/02/10/robert-hoskins-madonna-stalker_n_1267540.html" target="_blank">Robert Dewey Hoskins was sentenced to 10 years in jail in 1996</a> after stalking and threatening to kill Madonna. The singer reluctantly testified against the man, who was shot by her personal security after he jumped the fence of her Hollywood Hills home.

  • Alec Baldwin

    A Canadian actress, <a href="http://www.huffingtonpost.com/2012/04/10/alec-baldwin-stalker-ordered-to-stay-away_n_1414339.html" target="_blank">Genevieve Sabourin, was arrested on charges of stalking and aggravated harassment</a> after sending Alec Baldwin emails for several weeks and disturbing notes professing her love for him. Sabourin showed up at the Lincoln Center for the Performing Arts, where Baldwin was hosting a screening of "Last Tango in Paris," and she had to be removed by security. She also turned up unannounced at his home on Long Island and went to his address in lower Manhattan's Greenwich Village neighborhood while he wasn't there.

  • Conan O'Brien

    Reverend David Ajemian, <a href="http://www.huffingtonpost.com/huff-wires/20071107/conan-o-brien-stalking/" target="_blank">a priest in the Archdiocese of Boston, was arrested on charges of stalking late-night talk show host Conan O'Brien</a> by writing him threatening notes on parish letterhead, contacting his parents and showing up at his studio. The letters and e-mails, which started coming in Sept. 2006, continued even after Ajemian was asked to stop.

  • Mel Gibson

    Zack Sinclair, 34, <a href="http://www.people.com/people/article/0,,1076228,00.html" target="_blank">a drifter from Idaho, was sentenced to three years in prison in 2005 for stalking Mel Gibson</a>. Sinclair was arrested in Sept. 2004 after violating a restraining order that banned him from going within 100 yards of Gibson's Malibu compound where Gibson maintained a residence, children's school and chapel. "My wife was upset and worried," he said. "She didn't want to find him in the living room drinking tea."

  • Jodie Foster

    John Hinckley Jr., a 23-year-old who became obsessed with Foster after seeing her in "Taxi Driver," <a href="http://gawker.com/367076/people-cannot-stop-stalking-jodie-foster" target="_blank">followed her around Yale's campus, called her on the phone, and eventually shot president Ronald Reagan</a> and three others in an attempt to impress her.

  • Erin Andrews

    An Illinois insurance executive, <a href="http://sports.espn.go.com/espn/news/story?id=4998324" target="_blank">Michael David Barrett, secretly shot nude videos of ESPN reporter Erin Andrews</a> in hotel rooms. He was sentenced to 2 1/2 years in prison for interstate stalking after prosecutors accused him of following the reporter to at least three cities and shooting the videos through hotel peepholes.

  • David Letterman

    Margaret Mary Ray <a href="http://www.nytimes.com/1998/10/07/nyregion/the-woman-who-stalked-letterman-is-a-suicide.html" target="_blank">went in and out of jail for repeatedly stalking David Letterman</a>. She was first arrested while driving Letterman's Porsche through the Lincoln Tunnel and later for trespassing on his property in New Canaan, Conn., breaking into his house, and trying to reach him by telephone and in person. She later committed suicide in 1998.

  • Taylor Swift

    <a href="http://www.huffingtonpost.com/2013/05/16/taylor-swift-swim-stalker_n_3288175.html" target="_blank">Lucas Vorsteveld, 22, was arrested making a round-trip swim</a> from roughly a mile away from Swift's private beach, to her property and back in May 2013.

  • Paris Hilton

    Paris has had more than one stalking incident. <a href="http://www.huffingtonpost.com/2011/07/05/james-rainford-paris-hilton-stalker_n_890025.html" target="_blank">James Rainford was arrested after he attempted to grab Hilton's then-boyfriend</a>, Cy Waits, outside a Los Angeles courthouse where the pair testified against another man who attempted to burglarize the hotel heiress' home in the Hollywood Hills. Another man, Nathan Lee Parada, allegedly showed up outside the socialite's home wielding two knives.

  • Alyson Hannigan

    <a href="http://www.huffingtonpost.com/2013/02/13/alyson-hannigan-restraining-order_n_2682318.html" target="_blank">Hannigan received threatening messages from John Hobbs</a>, 43, and was granted a restraining order against him. Hannigan stated that Hobbs "posted a barrage of threatening messages directed at me and my family on various websites." The actress wrote that she had never met Hobbs, but his messages have suggested he would rape her and take her to the "after-life."

  • Blake Lively

    After showing up to the set of "Gossip Girl" and contacting her mother, <a href="http://www.dailymail.co.uk/tvshowbiz/article-2101308/Blake-Lively-stalker-Sergei-Mifle-hit-restraining-order.html#ixzz2f5jm7GNI" target="_blank">Blake Lively was forced to get a restraining order against Sergei Mifle</a>.

  • Ellen Page

    Threats made against Page via Twitter like "I'm going to murder Ellen Page. She's dead," caused the actress to be granted a search warrant to find the man behind the threatening posts. <a href="http://www.tmz.com/2013/01/16/ellen-page-restraining-order/#ixzz2f5lK9Cf4" target="_blank">The investigation yielded one suspect, a man named Joshua Michael Myers</a>, who was ordered not to contact the actress in any way for three years.