Dean and Sam will be keeping secrets form each other once again in season 9 of Supernatural.

Although it looked like the Winchester boys would be giving each other a fresh start following Sam's (Jared Padalecki) close brush with death in "Sacrifice," it appears Dean (Jensen Ackles) will be holding back some vital information from his little brother.

"There's a real surprise in the first episode that no one's going to see coming. There's going to be a few gasps," said executive producer Robert Singer, according to TV Guide. "It's something new for them. We've never done it before. I've never seen it done before."

When viewers left the boy's last season, Sam was in bad shape. After suffering all season form the effects of the trials, the younger Winchester seemed to take a turn for the worse when he attempted to let go of the power building inside of him. Apparently Dean's secret will explain how Sam manages to overcome this illness.

"The way Sam heals involves a big secret between Sam and Dean that Sam is not aware of and Dean keeps from him," Padalecki said at Comic-Con, according to Zap2It. "We'll see Sam going through a change, or changes, regularly, that I can't wait for."

Fans know that Dean would do, and has done, everything in his power to keep Sam alive. If Sam was angry when he found out Dean sold his soul in exchange for Sam's life in season 2, it seems like that reaction will pale in comparison to how he will react in the ninth season.

"Dean is continuing to lie to Sam, and he's hating it every step of the way," Padalecki told TV Line. "And Sam can't really tell. Sam's like, 'OK, I remember our conversation about teamwork, so I'm going to take you at your word.' But when Sam finds out, s--t's going to hit the fan."

Supernatural will return to the CW on October 15.

Tags: supernatural