The pair will join current anchor Matt Lauer on the show.
Pauley left the show in 1989 and Gumbel in 1997.
Zap2it.com said they last anchored the news together in January 2012 for "Today's" 60th anniversary.
The celebrity news website said NBC didn't offer a reason for next week's on-air reunion.
Members of Congress to keep receiving porn magazine
Rosie O'Donnell unveils nearly 50-pound weight loss