When Kim Kardashian became a mother to baby North West on June 15, her auntie duties shifted, according to Kourtney Kardashian who revealed her son Mason Disick is jealous of his new cousin. 

Kim has always had a close relationship with Mason, as shown on the Keeping Up With The Kardashians reality show, but since she gave birth to North, the attention has shifted on her own daughter.

"I think he gets a little bit jealous because he has a special relationship with his Aunt Kiki, and she takes away from that so he's still kind of adjusting." Kourtney told E! News on Sept. 15.

In a different interview with People magazine, the eldest Kardashian said that Mason gets a lot of attention from their family, but is very attached to Kim. 

"He and Kim were so close and so he doesn't understand because he's not the big center of attention," Kourtney said. "He's like, 'Why don't you like me anymore?' cause he sees [Kim] with the baby. I give him so much attention, and he gets so much attention from everyone else that I'm like I don't even know."

Kourtney also revealed that Mason's little sister, Penelope is in love with baby North. 

"Whenever [Penelope] sees [North] and, you know, the second she walks into the room, Penelope gets so excited," Kourtney told People on Sept. 15. "We never really had cousins that were close in age, so I'm excited."

Meanwhile, since the new baby, Kim has made a big change regarding her business. 

The reality star recently signed with Slate PR co-founder Ina Treciokas, after splitting with longtime publicist Jill Fritzo, who still represents the rest of the Kardashian family.

Sources told The New York Post that Kim made the switch "to set herself apart from the Kardashian p.r. machine, and Kanye West advised her to build her own team."