Recorded in London last autumn after seeing footage of the documentary, Meghan's new show will start streaming on Disney+ on April 3.
The doco follows African elephant Shani and her son Jomo as they are led by their matriarch, Gaia, across the Kalahari Desert.
Both British and US press have been consistent in their reviews, with critics giving the show a very average three stars. While they praise its stunning cinematography, Meghan's voiceover has been dubbed as pretty 'meh'.
"For her part, Markle's delivery of the commentary is wholesome and over-eager to please," added Empire's Ian Freer, who gave the film three stars.
He said that Meghan "just about stays the right side of annoying".
The Times (two stars): "Meghan Markle is swapping pomp and circumstance for schmaltz and cheesiness... The sense of performance, though, often feels overegged."
The Guardian (three stars): "Meghan takes to Disney-narration like an anthropomorphic duck to water."
The Telegraph (three stars): "[Meghan] turns out to be a fine match for the tone of the piece, which vacillates between regal and cutesy-poo with occasional gusts of girl-power uplift."
Variety (no rating): "Meghan Markle does an inviting version of the wholesome but amused Disney narrator singsong."
Empire (three stars): "Markle's delivery of the commentary is wholesome and over-eager to please."
The Express (four stars): "Meghan comes across very warmly, with most of her lines sounding like she’s beaming fondly at the elephants we’re watching... At times this can be a bit cheesy and sentimental in a classic American Disney kind of way."
The Times's Ed Potton (two stars): "Meghan is swapping pomp and circumstance for schmaltz and cheesiness", adding: "The departing Duchess of Sussex narrates Disney's tale of a herd of elephants crossing the Kalahari Desert from the Okavango delta to the Zambezi River, and boy does she lay it on thick."