The Seattle Seahawks can become the first team to win back-to-back Super Bowls in a decade after a 28-22 overtime play-off victory over the Green Bay Packers.
They will meet the last team to achieve that feat - the New England Patriots, who beat the Indianapolis Colts 45-7.
Seattle trailed 16-0 at half-time before two touchdowns in a minute put them back in contention.
A 35-yard touchdown in overtime then sealed their NFC victory.
Quarterback Russell Wilson, who passed to Jermaine Kearse for the winning touchdown three minutes into overtime to complete the comeback, said: "Everybody thought we were out of this game. You just trust the experience. You trust the guys you have around you."
The title game will take place at the University of Phoenix Stadium in Arizona on 1 February.
It will be a sixth Super Bowl appearance in 14 years for AFC champions New England, who won successive titles in 2004 and 2005, and an eighth appearance in total, equalling the Dallas Cowboys and Pittsburgh Steelers for the most in league history.