Katie Couric, Meredith Vieira Battle it Out in Morning TV Returns

Katie Couric and Meredith Vieira Credit: George Pimentel/WireImage.com; Bennett Raglin/WireImage

Monday was a big day for morning TV, as ABC and NBC both brought back beloved former anchors to appear on their daily news programs.

Filling in for vacationing regular cohost Robin Roberts, former Today anchor Katie Couric -- who left NBC in 2006 -- guest hosted Good Morning America Monday, her first appearance during a weeklong stint.

"As you know, I'm riding shotgun. I'm a little rusty," Couric, 55, joked to coanchor George Stephanopoulos, referring to her prior solo hosting gig as the anchor of the CBS Evening News.

Touted as a Today show "legend," Vieira, 58, stopped by 30 Rockefeller Plaza unannounced Monday morning to make a special announcement alongside former colleagues Matt Lauer and Ann Curry.

"It’s great for me, I'm going to be joining you all at the Olympics [in London], and I'm very excited," Vieira -- who served as Couric's Today successor -- said, confirming that she'll cohost this summer's opening ceremonies and report on other stories for the network. "In all the things I did I did in the Today show in five years, I think the Olympics is my very favorite experience."

Tell Us: Which morning show anchor do you prefer: Katie or Meredith?