Kylie Jenner showed off some majorly big boobs when she wore a see-through tank to shop at high-priced lingerie store Agent Provocateur in Los Angeles on Sunday. Seriously, Kim better watch herself because lookalike Kylie is totally going full-on Single White Female on her.

On Father's Day, the teen, who is dating the much older 25-year-old Tyga, was out and about doing some sexy shopping for her main man. We have to say we don't understand how this relationship is legal or how Tyga isn't locked up or something -- but apparently when you are banging a Kardashian you can get away with anything, even breaking those pesky statutory rape laws ...

Kylie may have spent some time with Caitlyn Jenner, but all we saw was lingerie shopping photos and the Instagram of her, Kendall and friend Laura Cruz, sunning themselves at the pool. She's absent from the off-roading family pics that Caitlyn posted. Clearly the girl's got her priorities in order!

Also: have Kylie's boobs always been that big? We get that she's a teen and is still growing into her body and that a good bra can do wonders but those things look surgically enhanced if you ask us. They're huuuuuge!

But what do we expect? The reality star was brought up in the self-absorbed world of the Kardashians with a momager for mother, who has given her carte blanche to do as she likes.

While Kylie may want the world to be envious of her fast-paced glam life -- mostly we feel sorry for her ...