It is not yet known whether Markle will discuss her departure from royal life.
The star was approached by film-makers Mark and Vanessa Berlowitz to narrate the documentary, and in return for lending her voice to the movie a donation will be made to a wildlife charity, The Sun reports.
Prince Harry, Meghan Markle, Beyonce, and Jay-Z at the European premiere of The Lion King. Photo / Getty Images
A clip promoting the appearance on the US morning talk show says: "On GMA Monday, Meghan Markle with an exclusive look at the Disney movie Elephant," a film which she narrated.
However, some critics were not a fan of Markle's voiceover performance.
Meghan Markle will appear on Good Morning America. Photo / AP
A majority of film critics rated Elephant three out of five stars, and accused the Duchess of Sussex's voice acting as being overdramatised.
The Disney documentary follows the journey of African elephants on an eight-month trek across the Kalahari Desert.
According to film critic Ed Potton from The Times of London, the actress-turned-royal has traded "pomp and circumstance for schmaltz and cheesiness".
"The silken tones that Meghan employed on the legal series Suits and which were often muzzled during her time as a full-time royal are now given free rein," he wrote.
"And yes, she certainly has an actor's way with a phrase and a likeable sense of mischief. 'Oh! Who did that?' she coos in mock disgust when one of the elephant calves breaks wind. The sense of performance, though, often feels overegged."
At the Lion King live-action premiere last year Prince Harry reportedly discussed Markle's interest in doing voiceover work with then-Disney CEO Bob Iger.
