Before Universal roped in Cillian Murphy for the Oppenheimer, he was previously mulled for the nuclear physicist role in the 2014's drama Manhattan.
Released almost a decade ago, the WGN America series was set in the wake of World War II to build the most deadly weapon man ever created: an atomic bomb in Los Alamos, N.M.
The show's focus, however, was on Frank Winter (John Benjamin Hickey), an exceptional and self-destructive physics professor recruited to be part of the Manhattan Project.
Meanwhile, the father of the atomic bomb made his entry in the first season, following his screen time was shot up in the next season.
In a chat with Vanity Fair, writer Lila Byock said, "When we were casting Oppenheimer, we went through a whole series of different ideas."
She continued, "There were actually some rock stars we considered," including David Bowie (who "was not available") and Beck.
As the creator Sam Shaw revealed, "We wanted Oppenheimer to feel both like he possessed a certain undeniable charisma, a presence onstage, but also that he was playing a different instrument. He needed to feel alien, or other, in some ways."
He continued, "A thousand percent, Cillian Murphy was on that list."
Planned as a six-season show, Manhattan was cancelled after Season 2, as the nuclear blast was planned in Japan at the Season 3 end, and the focus of the later seasons would be on the Cold War conflict fallout.