NEW YORK (AP) ? Two of Matt Lauer's former "Today" show co-hosts ? Katie Couric and Meredith Vieira ? are returning to the show for a week each in January with Savannah Guthrie on maternity leave. In 2012, she spent a week as a fill-in co-host on the NBC show's bitter rival, ABC's "Good Morning America." "It's going to be fun," said Lauer on Thursday, describing it as a "walk down memory lane." Guthrie gave birth to a boy, Charles Max Feldman, on Dec.