Showdown! Kylie Confronts Tyga's Alleged Mistress

Kylie Jenner's boyfriend Tyga has given her yet another reason to dump him, allegedly cheating on her with Brazilian model Annalu Cardoso. But instead of ignoring the hype or taking it up with Tyga himself, RadarOnline.com exclusively learned from a source close to the 18-year-old Keeping up with the Kardashians reality star that she lashed out at the other woman!

"Kylie always gives Tyga the benefit of the doubt because most of these girls that claim to have slept with him are just wanting to get famous," the insider said.

According to Us Weekly, the 26-year-old rapper and Brazilian-born model Annalu Cardoso – who bears a striking resemblance to Jenner – first met on the set of one of Tyga's music video shoots and continued their affair during the filming of his MTV2 show, Kingin' With Tyga.

Cardoso herself spilled the beans on their supposed sexual trysts to the magazine, claiming that it started off as texting and flirting, but eventually became intimate.

The source told RadarOnline.com today that, after hearing the news, "Kylie reached out to this girl and she demanded proof of the affair."

"She wants to see text messages and photos," said the source. "Kylie need to know if what this girl said is true. And if it is, she will have no other choice but to leave Tyga."

As RadarOnline.com previously reported, this is not the first time that the rapper has been accused of being unfaithful to his young plastic princess: He was also accused of cheating on her with transgender model and porn star Mia Isabella, which he denied.

"She can only hear these kinds of rumors so many times before she'll cut him out of her life," the source said.

Tyra's rep did not immediately respond to RadarOnline.com's request for comment.

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