Since Kourtney Kardashian and Justin Bieber's May-December romance has been exposed, the two have been enjoying much publicity these days. The latest talks claim that Kourtney is now obsessed to get thinner for Justin. There are also reports claiming that her obsession turned to so much insecurity with Justin's ex Selena Gomez's almost perfect body.

Kourtney and Justin's 15-year-age gap is allegedly not helping her be confident with her figure. She's now conscious about her skin, diet and workout. Ever since their hook-up has been revealed, the 36-year-old reality star just wants to look more stunning for the "What Do You Mean" crooner's eyes, Hollywood Life reports.

"Kourtney is getting more and more obsessed with her looks since hooking up with Justin. He's only 21 and has perfect skin and a flawless fat-free body. Kourtney is working out like never before, making sure she's super skinny," a source said.

Kourtney reportedly would not let Justin see her without makeup. It is said that she feels terrible as her insecurities began to grow more with their age difference. The reports went up a gear when it was said that the mother of three feels threatened by the Canadian singer's former girlfriend's almost perfect body. Kourtney reportedly doesn't want to see Selena's hot new video "Hands To Myself" where the latter reportedly looks so attractive and sexy.

Meanwhile, it was earlier reported that Kourtney and Justin's hook-up has been going on for about four months now, according to Closer Online. The "Sorry" singer reportedly bragged to his friends about it.

"Oh, yeah, that's definitely happening and has been for some time now," one source claimed about Kourtney and Justin's romance. "Every time Kourtney and Justin are together they're extremely flirtatious. They text each other all the time."

Kourtney and Justin were first seen together in public when they had dinner at Nice Guy in Los Angeles. The couple also went to Halowwen Horror Nights attraction after the dinner.