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Leslie Odom, Jr.
Years before he would pick up a Tony nomination for his role of Aaron Burr in the runaway Broadway hit Hamilton, Leslie Odom, Jr. popped up in one 2008 episode of Grey's Anatomy. The celebrated star played P.J. Walling, a young man who reluctantly participates in a domino surgery of kidney transplants, which his estranged father is benefitting from.
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A few years before she earned her first Golden Globe and Emmy nominations, Sarah Paulson booked a one-episode gig in Grey's Anatomy. The famed actress played Dr. Ellis Grey in a 2010 flashback episode, depicting Meredith's mother during her residency.
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Back in her Sonny with a Chance days, Demi Lovato stopped by one 2010 episode of Grey's Anatomy. The pop star played Hayley May, a patient whose condition was difficult to diagnose and made those around her doubt her symptoms.
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After saying goodbye to Gilmore Girls' Doyle McMaster, Danny Strong played a man named Paul in one 2012 episode of Grey's Anatomy. He visits the hospital after getting attacked by a lion belonging to his girlfriend.
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Rita Moreno brought her star power to Grey's in the 12th season. She portrayed Gayle, a woman who is visiting her cheating husband in the hospital.
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Katie Lowes made her way to Shondaland before she ever played Scandal's Quinn Perkins, when she appeared in a 2011 episode of Grey's Anatomy. Lowes played an unnamed blood donor.
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The same year that she kicked off her gig as Peggy Olson on Mad Men, Elisabeth Moss appeared in a 2007 episode of Grey's Anatomy as Nina Rogerson. She played the daughter to a woman with a delicate condition, who becomes obsessed with the patient's care.
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Within months of making his debut as Friday Night Lights' Landry Clarke, Jesse Plemons dropped in on a 2006 episode of Grey's Anatomy. He played Jake Burton, a patient with a unique condition that makes him look like a lion.
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Former child star Keke Palmer picked up a one-episode gig on Grey's Anatomy in 2014. Before hitting Scream Queens, she played Cheryl Jeffries, a pregnant patient visiting the hospital who wants to participate in a clinical trial.
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In 2009, Faye Dunaway popped up in an episode of Grey's Anatomy, playing Dr. Margaret Campbell. Her character was one of the first powerhouse surgeons at the hospital who drops back in for a procedure.
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Ten years after playing Toula Portokalos in My Big Fat Greek Wedding, Nia Vardalos appeared in a 2012 episode of Grey's Anatomy as Karen. She played a patient undergoing a liver transplant.
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Kurt Fuller added to his extensive filmography in 2007 with an episode of Grey's Anatomy. He played Jerry, a patient with an extensive run of bad luck.
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Veteran star Annie Potts dropped in on Grey's Anatomy's 10th season in 2013. She played Joyce Bosco, a woman who is at the hospital with her husband.
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Ethan Embry popped up in a 2012 episode of Grey's as Dr. David Moore. He played a doctor who worked with Arizona after the loss of her leg.
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After wrapping her run as Happy Endings' Penny Hartz, Casey Wilson appeared in a one-off episode of Grey's Anatomy in the show's 12th season. She played Courtney Hall, a pregnant patient who chats with the doctors about their taxes.
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In the years between her stint as Paris Geller on Gilmore Girls and as Amanda Tanner on Scandal, Liza Weil appeared in a 2009 episode of Grey's Anatomy. Weil played Allison Clark, a cancer patient who bonds with Izzie.
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Mary Pat Gleason
Mary Pat Gleason found a spot in a 2013 episode of Grey's Anatomy. The veteran actress played Marge Walker, a patient with one gnarly infection.
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In 2010, Jamie Chung made an appearance in Grey's Anatomy as Trina Paiz. She found herself in the hospital after falling and cutting her ear.
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Famed performer Natalie Cole appeared in a 2006 episode of Grey's Anatomy. The late star, who died in 2015, played Sylvia Booker, a patient who comes into the hospital with a fork in her neck and leaves after undergoing surgery for a seemingly inoperable tumor.
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After playing Gypsy on Gilmore Girls and Gwen Chambers on Parenthood, Rose Abdoo played Dr. Kim Dawson in one 2014 episode of Grey's Anatomy. She appeared as a therapist who works with Callie and Arizona.
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Mary Lynn Rajskub
Mary Lynn Rajskub appeared in an episode of Grey's Anatomy in 2012. The 24 actress portrayed Marion Steiner, a woman who contracts a parasite after traveling abroad.
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The late Doris Roberts joined Grey's Anatomy for one episode in 2011, a few years after she wrapped her run as Marie Barone on Everybody Loves Raymond. Roberts played Gladys Pulcher, a patient who comes to the hospital after her surgery does not go as planned.
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Years before he began his famed Shondaland turn as David Rosen in Scandal, Josh Malina appeared in one 2008 episode of Grey's Anatomy as Seth Hammer. He plays a man who visits the hospital with his hypochondriac wife.
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Sara Gilbert played a character named Kim Allen in a 2010 episode of Grey's Anatomy. She appeared as a woman who has come to the hospital to die after her cancer has gone too far.
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Jurnee Smollett picked up a two-episode arc on Grey's Anatomy in 2008. The Friday Night Lights and True Blood actress played Beth Monroe, a patient participating in a clinical trial who is in love with a fellow patient.
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Lee Majors made his appearance on Grey's Anatomy in 2011. He played Chuck Cain, a patient who has his priorities mixed up when he focuses on his looks, rather than his health.
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In the midst of her Private Practice run, Audra McDonald stopped by Grey's Anatomy as Dr. Naomi Bennett. She played her Private Practice character, finding herself in Seattle as a support system for Addison, whose brother is undergoing surgery.
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Ernie Hudson made an appearance in one 2011 episode of Grey's Anatomy. The prolific star took on the role of Dr. Brad McDougall, a doctor on the hospital's competing baseball team.
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Early in her career, Abigail Breslin picked up a one-episode gig on Grey's Anatomy as Megan Clover. She played a little girl who bonds with Alex over her inability to feel pain.
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Years before she played Amber Holt on Parenthood, Mae Whitman appeared in two episodes of Grey's Anatomy as a patient named Heather Douglas. A teenager, Heather is bitter over her seemingly dire condition, but gets new hope thanks to Izzie.
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Mandy Moore did a four-episode stint on Grey's Anatomy in 2010. The former pop star and A Walk to Remember actress played a woman named Mary Portman. She is a patient at the hospital during the deadly shooting and is caught up in the violence but makes it out alive, only to die months later.
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Bernadette Peters joined Grey's Anatomy for two episodes in 2008. Peters portrayed Sarabeth Breyers, a woman who is at the hospital with her friends after the women and their husbands get into a car accident.
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Veronica Cartwright appeared in two episodes of Grey's Anatomy in 2013 as Lydia Ashford. She plays a patient in the hospital who is worried about her the state of her house after a violent storm.
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Years before she made her debut as Mellie Grant on Scandal, Bellamy Young appeared in two 2007 episodes of Grey's Anatomy. She played Kathy, a patient who comes in for a sports injury but ends up dealing with her relationship problems.
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Christina Ricci hit the small screen in 2006 for two tense episodes of Grey's Anatomy. She played Hannah Davies, a paramedic who finds herself in a sticky situation when a patient comes in with live ammunition in his body.
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In the midst of his run as Friday Night Lights' Matt Saracen, Zach Gilford played a character named Charlie Lowell in one 2009 episode of Grey's Anatomy. He played a soldier who's working to get in fighting condition to go back to the battle field.