The drama will focus on Maya (Amber Stevens), a documentary filmmaker working on a film about deceased rock star Dakota.
Travelling back in time to the 1990s, Maya meets and falls in love with the musician, becoming determined to prevent his death when she returns to the present.
Horner has now been confirmed to appear opposite Stevens, reports Deadline.
The Australian actor is best known for starring in fantasy series Legend of the Seeker from 2008 until the show's cancellation in 2010.
Other drama pilots picked up by The CW include an updated Beauty and the Beast starring Kristin Kreuk (Smallville) and Jay Ryan (Terra Nova) and the futuristic The Selection.
Comic book adaptation Arrow and medical drama First Cut are also in the works.
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