On 'The Early Show' (weekdays, 7AM ET on CBS), 'Survivor: Nicaragua' host Jeff Probst introduced several cast members from the upcoming 21st season and explained this season's twist.

The new cast includes Brenda Lowe, a young competitor that Probst describes as a "black widow" and Kelly Bruno, who has an artificial leg. Most notably, 'Survivor: Nicaragua' will feature a battle of the ages theme with a young tribe pitted against an older one that includes former NFL coach Jimmy Johnson.