Supernatural's biggest fans likely know the story of how Jared Padalecki and Jensen Ackles were cast as the leads of the long-running CW show. (Both actors auditioned to play Sam Winchester, then Ackles piped up with his interest in playing the smart-ass, elder Winchester brother, Dean.) But now Padalecki is sharing a piece of the casting story that Supernatural fans may have not heard.

In a phone interview in December shortly after wrapping production on Supernatural's 300th episode, Padalecki prefaced his recollections of the casting experience with a laugh, saying of series creator Eric Kripke, "I'm gonna totally sell him out."

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Padalecki recalled what his manager told him of his initial contact with Kripke: "Eric's like, 'Uh, I've seen Gilmore Girls. We want Sam to be really smart.' And so my manager had to go, 'Uh, well, my client is a National Merit Scholar.'"

In 2005, at the time Supernatural premiered, TV viewers knew Padalecki best as Rory Gilmore's first boyfriend, Dean Forester, a character who does not share Rory's love of reading and had little hope of ever appearing to be a brain next to the witty Gilmore ladies. Sam Winchester, meanwhile, at Supernatural's start, is a student at Stanford University applying to law schools with a 174 score on the LSAT, then a monster-hunter who nerds out over researching "the lore."

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Padalecki said after that conversation between his manager and Kripke, his manager offered some advice for his Supernatural audition: "My manager called me and was like, 'Hey listen, don't be charismatic, don't be charming. Just be hyper-intelligent.' So when I met [Kripke], I felt like I was in this weird zone where I was trying to channel my inner David Duchovny or something." (Fun fact: Duchovny shares an alma mater with Rory Gilmore — he earned an M.A. in English literature from Yale University.)

Jared Padalecki as Supernatural's Sam Winchester, left, and Gilmore Girls' Dean Forester. Photo: Dean Buscher/The CW; The WB

"Now we laugh about it," Padalecki continued. "I tease [Kripke] all the time. I'm like, 'Hey man, thanks for thinking I'm smart enough to play Sam.'"

Padalecki can look forward to playing Sam Winchester for at least one more season. Ahead of Supernatural's landmark 300th episode, The CW president Mark Pedowitz announced the show's Season 15 renewal on Thursday.

Supernatural's 300th episode airs Thursday, Feb. 7 at 8/7c on The CW.

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