Kourtney Kardashian's daughter Penelope is now two months old, but there's another little one running around the Kardashians' Miami pad getting most of big brother Mason's attention: Kim Kardashian's kitty, Mercy!
"He just cannot live without her!" Kim, 31, told Us Weekly at Tuesday's Midori Makeovers event at L.A.'s Fred Segal Salon of her nephew, 2, and feline friend. Mercy was a gift from Kim's boyfriend Kanye West that she named after West's latest single. "I'm going to have a really big problem if he gets too attached."
In the Sunshine State to film her E! spinoff Kourtney & Kim Take Miami, Kim says Mason -- who became a big brother July 9 when Kourtney and Scott Disick welcomed Penelope -- serves as a constant companion for her new cat. "I get to wake up with Mason every day -- he actually wakes me up every day looking for my kitty," she says. "We can maybe share custody, so when I'm on the road there'll be a permanent babysitter."
When Mason isn't palling around with Mercy, he's bonding with mom Kourtney and baby Penelope. "He's so good. He loves her," reports Aunt Kim.
Though Kim finds things hectic, her sister is "effortlessly" juggling parenting duties with her two kids while working at the sisters' busy DASH Miami store.
"It's a lot to juggle when she works as much as she does. [Everything Kourtney does now requires] extra preparation, extra time. You need a bigger car, more car seats -- an extra sister!" reasons Kim of Kourtney, 33. "It's hard with two kids. She does it so effortlessly. I have a lot of friends who have two kids and she definitely makes it seem the easiest."