The highly anticipated new season of "Survivor: Philippines" launches not only features 18 contestants competing to win one million dollars in the Philippines, but a series of unprecedented twists and changes to the show's format.

This time, three returning cast members will join the new 15 competitors. There has been speculation that the ones returning from past seasons, are competitors who had to leave the show because of medical reasons.

Last years season saw one of the biggest changesto the format with both tribes residing together at the same camp. This had never been done before on the 24 seasons of the show, except for briefly during a fake merge on "Survivor: Thailand." During "Survivor: Palau"  the two teams lived together before they were split into two tribes.

Each returning player from previous survivors will be on a different tribe, which means the show is moving back to the three-tribe format. This is the first time they are doing this since season 8,"Survivor: All Stars." 

Jeff Probst said to Entertainment Weekly, "First we decided on three tribes. "That was the first thing. And that was just an effort to change up the way the numbers were playing. People were locking into these alliances of five. So we thought, okay, let's try a three-tribe scenario and see what that does. Once we had the three tribes, we talked about are we going to do returnees? I love returnees. I love second chances. I love the losers bracket in sports. I love all of it. So I love these guys coming back. And then we hit on the evacuees and went, that's it! These are true second chancers. They were pulled from the game. They didn't quit. They didn't get voted out. They were yanked."

This twist to the show puts new competitors against veterans, so interesting things should conspire. The show is set to air on Sept 19 on CBS.

See here for more info about Survivor's new cast members.