See the Legendary Cast of How I Met Your Mother Before the Fame!

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Who Am I?

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Joe Manganiello--NOW

The sullen looking teenager certainly turned into a supremely handsome man. Manganiello played Marshall's law school buddy, Brad, in a couple episodes during the series.

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Alex Trebek--NOW

The Jeopardy host guest starred as himself in seasons 6 and 8 of HIMYM.

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Kyle MacLachlan--NOW

The ever handsome MacLachlan was a recurring guest star in three seasons of HIMYM. As The Captain, he was decidedly more goofy than when he was in any David Lynch project.

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Alyson Hannigan--NOW

The hilarious Alyson Hannigan was perfect as Lily Aldrin, one of the core group. We've seen Lily's college goth roots, her crushing on BFF Robin and the evolution of her relationship with Marshall. Her only fault may be her inability to keep a secret, which she later rectifies.

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Cobie Smulders--NOW

Cobie Smulders played one of our all-time favorite ladies on TV as Robin Scherbatsky. A scotch drinking, Canadian pop star-turned journalist, Robin's friendships with the gang and her romance with Barney made us just love her even more.

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Jason Segel--NOW

Segel played Marshall Eriksen, the other half of Lily and Marshall. He's tall, easygoing and his favorite flower is the calla lily. Alongside showing his comedic timing, Segel has shown some great dramatic work on HIMYM.

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Josh Radnor--NOW

Josh Radnor's Ted Mosby has been on a long journey over the last nine seasons to meet the titular mother. He's dated terrible people, fallen in love and made some questionable shoe choices but we've always been rooting for his happy ending.

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Neil Patrick Harris--NOW

Teen star Neil Patrick Harris aged gracefully into an adult star while playing, at times, questionable dudes. He made Barney Stinson, a womanizing, Bro Code living guy into a complex and loveable character.

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Britney Spears--NOW

Pop Queen Britney Spears played a small guest role as Abby, a receptionist at Ted's dermatologist, who was crushing on Ted and eventually slept with Barney.

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Enrique Iglesias--NOW

Enrique Iglesias played Gael, Robin's rebound boyfriend, post her breakup with Ted in season three. Marshall initially hated him but ended up falling for Gael's singing and massage skills.

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James Van Der Beek--NOW

James Van Der Beek played Robin's first love, Simon, a singer in a band who appeared in one of her music videos. He broke Robin's heart but even when she was reunited with him still thought he was the coolest. (He wasn't.)

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Katie Holmes--NOW

HIMYM certainly tapped the Dawson's Creek resources! Katie Holmes played Naomi--The Slutty Pumpkin--aka the girl who Ted thought was his dreamgirl. Unfortunately, their initial chemistry didn't last.

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John Lithgow--NOW

Coming off a terrifying turn on Dexter, Lithgow played Jerome, Barney's real father. Barney was convinced Jerome was his Uncle Jerry and that Bob Barker was his real father but after much searching and talking, the two finally connected.

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Laura Prepon--NOW

Laura Prepon hilariously played Karen, Ted's on-off high school college girlfriend, who helped highlight some of Ted's worst qualities--mainly his pretension.

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Rachel Bilson--NOW

Before Ted knew The Mother, he dated her roommate Cindy (Bilson), who was a graduate student where he taught. They broke up and later Cindy realized she wanted much different things than Ted.

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Sarah Chalke--NOW

Sarah Chalke played a hugely important role in Ted's romantic development, as Stella, the dermatologist he fell hard for. The two ended up getting engaged but she left him at the altar for her high school love, Tony, with whom she had a daughter.