Kylie Jenner: PUMA's Letting Me Rock Adidas ... So I Am

Kylie Jenner just confused everyone by stepping out in Adidas kicks, almost at the exact same time PUMA announced she's the feet of their brand ... and TMZ now has the real story behind the deal.

Our sources say Kanye -- who has a big deal with Adidas -- was pissed off when he got wind Kylie was negotiating with PUMA and vowed it would never happen because it would be like a family betrayal.

We've learned by the time Kanye got wind of a deal between PUMA and Kylie, the contract was already signed. We're told Kanye was initially angry, but he spoke with Kylie and she explained she got a "carve out," and PUMA agreed to let her wear Adidas in addition to PUMA.

Our sources say Kylie explained to Kanye she got the carve out for him, and at this point couldn't back out or she'd be sued. She added the deal was only for 6 months.

We're told Kanye's now actually ok with the deal, and Kylie's supporting him by stepping out today in Kanye's brand.