For the first time since she stepped down from NBC's Today show six years ago, Katie Couric will return to doing what she had done from 1991 to 2006, co-hosting a morning network talk show. But this time the show that she'll co-host will be the one that she competed against for 15 years, ABC's Good Morning America . Couric, who now has a deal with ABC News after leaving the anchor desk at the CBS Evening News , will be filling in for Robin Roberts on the morning show, joining George Stephanopoulos, Josh Elliott, Sam Champion and Lara Spencer. She is due to launch a talk show of her own in The Fall.