The CW drama is currently casting for the role of Amelia, a doctor in her late 20s to early 30s, Zap2it reports.
The recurring character will first appear in the third episode of the eighth season, directed by Supernatural star Jensen Ackles.
Described as "a brave, sweet, smart, sarcastic woman", Amelia will first encounter Sam after suffering a personal tragedy.
The eighth season of Supernatural will see Jeremy Carver replace Sera Gamble as showrunner.
Rick Worthy (the Alpha Vampire) recently hinted that his villainous character could return in the new episodes.
Supernatural returns to The CW on Wednesday, October 3 at 9/8c. In the UK, the series airs on Sky Living.
> Supernatural: Season seven finale 'Survival of the Fittest' recap
Watch a clip from the Supernatural season seven finale below: