Victoria's Secret model Adriana, 34, took to social media to defend herself against the accusations, which were published in Britain's OK! magazine, and suggest she and Alessandra trashed the girls in a Mean Girls-style rant over brunch at a Los Angeles restaurant last month (Mar16).
The Brazilians were reportedly overheard making fun of Kendall's "boring image and disastrous family" and stated both girls are "just pretty faces who don't have any unique talent".
Posting a clipping of the magazine article on social media, Adriana called the rumours "absolutely not true", adding, "magazines sometimes make a big buzz to sell, creating negative and false reports."
"This kind of news goes against my character and against the values that my mother taught me," she added.
Adriana and Gigi reportedly became rivals after both modelled for the American lingerie line and became ambassadors for the make-up brand Maybelline at the same time.
Adriana and Alessandra, 34, walked the annual Victoria's Secret Fashion Show as part of the brand's permanent team of model Angels last year (Nov15), when Kendall and Gigi, both 20, made their debut on the brand's catwalk.
The newcomers reportedly ruffled some feathers with their arrival and following the show last year, Adriana, who has 16 years experience with the brand, was quoted as saying, "Those two girls were gorgeous, but you have to have character (to make it as a model)."
Adriana refutes this quote too, stating, "I absolutely love those two girls and I can't believe sometimes how negative those magazines can be."
Alessandra Ambrosio is yet to comment on the story.