Los Angeles, California - After reports claimed that Kylie Jenner jetted off with Timothée Chalamet for her birthday, new rumors insist that the two are on the rocks!

Following the 27-year-old mogul's "best birthday ever," In Touch Weekly dished that upon Kylie's discovered that the Dune star has allegedly been unfaithful behind her back!

An insider said, "Kylie and Timothée have never said they're exclusive, so in his book, he hasn't done anything wrong."

The tipster continued that the Kardashians star "feels differently."

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"She's betrayed, not to mention humiliated," they added.

A rep for the Wonka star has denied the gossip, but the confidant insists that Timothée can't resist the perks of his global fame since "women do not say no to him."

"Even though she didn't want to label their relationship, she thought he was The One," the source said of Kylie's feelings. "Little did she know he's a raging player. Women are definitely his vice."

Kylie and Timothée have been privately dating for the last 16 months and are said to be "very serious," but is there trouble in paradise at last?