Photo/Illutration A captured image of a statement titled “Apology for cartoon review project of 'Frozen 2,' ” which was issued on Dec. 5 on the official website of Walt Disney Co. (Japan) (Mitsuko Nagasawa)

Favorable reviews of "Frozen 2" posted online by manga artists in Japan that included cartoons of the characters are drawing a frosty reception after it was discovered that they were paid to promote the new film.

Walt Disney Co. (Japan), the distributor of the film, on Dec. 5 issued an apology on its website in which the company pledged to prevent a recurrence.

"Frozen 2" is currently being screened in Japan. Walt Disney Co. (Japan) asked several manga artists via a contracted company to draw and post cartoons that contain their reviews of the movie on their Twitter accounts for the company's cartoon review project. The company signed a contract to pay the artists for their work.

The cartoons in question were drawn by seven manga artists and posted on Twitter on the afternoon of Dec. 3. Characters from "Frozen 2" appear in all the cartoons along with positive reviews of the film.

Since those cartoons were posted at almost the same time, social media users and others suspected that they were part of “stealth marketing,” a marketing strategy in which a product is promoted through a campaign without mentioning that it is for promotional purposes.

Some of the artists revealed on the morning of Dec. 4 that their cartoons were done to promote the film and posted an apology on Twitter.

Walt Disney Co. (Japan) said the cartoons were supposed to include an explanation that clearly states they were done for promotional purposes.

The company added, “We failed to have good communications with the artists and ended up with the cartoons having no mention of their purposes on the initial posts.”