"Good Morning America' -- born Nov. 3, 1975 -- is not about the let the 40th birthday pass by unnoticed, so a 40-hour marathon will be noticed, right? 

The show announced Thursday that the 40-hour marathon will stream live, beginning Nov. 17 at 5, and conclude two days later, at the end of "GMA's" Nov. 19 telecast. Portions of the marathon will air on the network, but the vast bulk will stream at abcnews.com/live.

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Per "GMA," here's what to expect over those two days, and you may be certain, some of this will appear during the broadcast portions: One Direction will perform; "The Hunger Games Mockingjay Part 2" cast will be on the Nov. 18 program...

Of note, ABC promises an "historic" reunion over those days. Some of the boldface names to return to Times Square (many of whom worked at the old studios some 20 blocks north):

David Hartman, Nancy Dussault, Sandy Hill, Joan Lunden, Charlie Gibson, Kevin Newman, Lisa McRee, Diane Sawyer, Robin Roberts, George Stephanopoulos, Lara Spencer, Steve Bell, Kathleen Sullivan, Mike Schneider, Morton Dean, Elizabeth Vargas, Antonio Mora, Josh Elliott, Juju Chang, Amy Robach, John Coleman, Spencer Christian, Mike Barz, Sam Champion, Ginger Zee, Dr. Tim Johnson, Dr. Nancy Snyderman, Dr. Jen Ashton, Dr. Richard Besser.