Stephen Colbert and the cast of “Modern Family” are next up to temporarily replace “Good Morning America” host Robin Roberts, who is scheduled to undergo a bone marrow* transplant this week.

The surging ABC morning show hasn’t missed a beat since Roberts exited on August 30. The co-host has MDS, a blood and bone marrow disease, and is out indefinitely* for treatment that includes a transplant of marrow donated by her sister, Sally-Ann Roberts.

Tom Cibrowski, the show’s senior executive producer, offered more details about the schedule of substitutes for Roberts, which is expected to include Oprah Winfrey and journalist Barbara Walters, Katie Couric and Diane Sawyer next month.

Celebrities will be deployed in much the same way as Jessica Simpson was one day last week, appearing on the pop culture-heavy second hour alongside show regulars George Stephanopoulos, Josh Elliott, Lara Spencer and Amy Robach.

“It shows them in a different light for a little bit and you get to see them do something different,” Cibrowski said. “It might be a little funny if they have to read the prompter and there’s some slip-up*. It’s all spontaneous*.”

The show will feature a different cast member of “Modern Family” each day for a week as the new television season begins. Actor Rob Lowe is also scheduled, Cibrowski said.(SD-Agencies)