Nothing lasts forever, and while it seemed like "Supernatural" might be the exception to that rule, it's unfortunately not the case. Stars Jared Padalecki and Jensen Ackles made the announcement Friday alongside their trusted angel sidekick, Misha Collins, that the show's upcoming 15th season will be its last."We just told the crew that although we're very, very excited about moving into our 15th season, it will be our last," Ackles said in a video message to fans.Ackles went on: "Fifteneen years of a show that's changed my life. I know it's changed these two guys' lives. We just wanted you to hear it from us, that though we're excited about next year, it will be the finale. The big, grand finale of an institution.""We cried some tears," a clearly emotional Padalecki added. "We'll cry some more."The decision to wrap up any show after 15 seasons shouldn't usually be surprising, but in this case, CW boss Mark Pedowitz had just nodded to a future beyond season 15 at the TCA press tour in January.Padalecki and Ackles had also said that they'd hoped to "keep heads down and keep moving forward" when "Supernatural" reached its milestone 300th episode earlier this year.Friday's announcement was made just a few weeks after Stephen Amell confirmed his own long-running CW series, "Arrow," will also be ending next season.