Jared Padalecki kept Walker's Season 1 finale reveal secret since the beginning of shooting

The New York Times

“The big difficulty for me was having to tell white lies to my friends and family and fellow cast and crew,” Padalecki said of last night's season finale “I didn’t feel good about it, but I’m learning to put that line between friend and fellow actor.” ALSO: Padalecki launches a GoFundMe for a Supernatural "family member" who died from breast cancer.