The Recording Academy said Perry will perform in Canada, while Swift will take the stage in Australia. The artists will appear via satellite on the program, which is to air on CBS.
Scheduled to perform on the main stage in Los Angeles are Earth, Wind & Fire and T.I., who have joined a lineup of singers that includes Keith Urban, Macklemore & Ryan Lewis, Robin Thicke, Lorde and Miguel.
LL COOL J is to serve as host of the 1-hour special.
2014: The Year in Music [PHOTOS]