"Good Morning America" will be getting a dose of truthiness in the coming weeks.
Also slated to guest-host in Roberts' absence: Cast members of ABC's primetime hit "Modern Family," a different one of which will guest-host each day for a week.
"Parks and Recreation" star Rob Lowe has also been tapped to fill in.
Roberts took medical leave at the end of August to prepare for a bone marrow transplant. The host, 51, has been diagnosed with the blood and bone marrow disease myelodysplastic syndrome, also referred to as MDS. (USA Today reports that Roberts will undergo the transplant this week.)
"GMA" senior executive producer Tom Cibrowski told the AP that the celebrity guest hosts will be featured in the show's second hour, which leans toward pop culture topics, and that the show is hoping that the guests will provide some spontaneous laughs for the audience.
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"It shows them in a different light for a little bit and you get to see them do something different," said Cibrowski. "It might be a little funny if they have to read the prompter and there's some slip-up. It's all spontaneous."
In addition to the celebrity guests, seasoned television journalists Diane Sawyer, Katie Couric and Barbara Walters are expected to fill in for Roberts, as is Oprah Winfrey.