Kim with Mercy (London Ent/Splash News)Kim Kardashian is mourning the loss of her furry friend.

Just three months after the reality TV star was first seen cuddling the white Persian teacup kitty, Mercy, the reality TV star has shared the sad news that the cat, which was a gift from boyfriend Kanye West, has died.

Aniston and Norman. (Splash News/INFDaily.com)There's a fine line between love and obsession when it comes to pets and their owners. Take for example Jennifer Aniston, who got her dog Norman's name tattooed on her foot after his 2011 death, or Adam Sandler, who made his bulldog Meatball his best man at his wedding and then held a 100-person memorial at his home when the pooch passed in 2004. Other stars like to memorialize their time with their beloved pets by sitting for celeb photographer Christopher Ameruoso, who has captured Selena Gomez, Ozzy Osbourne, and Courteney Cox with their treasured furry friends over the years. His craziest photo shoot? Amerouso tells "Celebrity Pet Project's" Theo Von about the time he convinced Megan Fox to pose with a real fox!

Leona Lewis (Optic Photos, PacificCoastNews.com)Leona Lewis is "Bleeding Love" for animals in need.

A long-time supporter of Hopefield Animal Sanctuary in Brentwood, England, the 27-year-old hosted and performed at the organization's Christmas fete over the weekend. The British singer — who kept warm in a plaid coat and Hunter boots — has been an avid fundraiser for the animal refuge, which cares for 200 sick, unwanted, and mistreated animals.

Drita D'Avanzo (Splash News)There is no doubt about it: Drita D'Avanzo is one tough cookie on "Mob Wives." She's not afraid to get in anyone's face, and she's not big on backing down. Well, her toy poodle seems to have the same feisty attitude. The only problem? Lucky is so tiny that a breeze would win in a showdown.

"My dog thinks she's 180 pounds and she's three pounds," the 35-year-old makeup artist tells omg!. "She has that Napoleon syndrome."

Simon Cowell (Getty Images)Simon Cowell is a big fan of flippers — and we're not talking about beach gear.

"The X Factor" judge, who is known for being a bit of a curmudgeon, is apparently likes penguins so much that he said he would love to have one of the flightless birds to call his own.

"Watching Mr. Poppers Penguins again," the 52-year-old tweeted this week. "I love this film. I really do want a pet penguin."

Gyllenhaal and Atticus. (Splash News)Massages, manicures, and meditation aren't just for humans anymore. Many Hollywood celebs like Jake Gyllenhaal, Nicole Richie, and Mischa Barton often let their furry best friends indulge in a little R&R just like they do. "Celebrity Pet Project's" Theo Von gets the scoop from dog trainer and L.A. Dogworks owner Andrew Rosenthal about what goes into a "paw-dicure" and whose pups get the kinks worked out in the Zen Den. And keep an eye out for a guest appearance by Amanda Bynes' dog Tiara, who has been staying at L.A. Dogworks while her owner is in New York City!

Miley and the puppy that almost became her seventh. (Splash)Looks like that pet pig wasn't the only live gift Miley Cyrus got for her 20^th birthday last week. On Monday, the former "Hannah Montana" star and her sister Noah stopped by Spot! Pet Boutique in Los Angeles to pick up some goodies for a new puppy the family recently adopted — but another little cutie caught her eye in the store. Miley, dressed for the holiday season in a red sweater, was seen smothering an adorable brown puppy with kisses and hugs as she perused the shelves of dog clothing.

Britney Spears and her new puppy, Hannah (Twitter)Britney Spears has a furry new addition!