Like many celebrity couples caught in a nasty break up, Kristen Stewart and Robert Pattinson have found themselves in a brutal custody battle. No, it's not over half-vampire Renesmee, but instead over their rescue dog, Bear.

The "Twilight" couple had adopted Bear when he was a puppy from a high-kill New Orleans shelter. The dog suffers from Parvo disease, a deadly viral infection, and likely would had died had Pattinson and Stewart not taken it and provided treatment.

Since Stewart's infidelities with married "Snow White and the Huntsman" director Rupert Sanders came to light, both Stewart and Pattinson, her boyfriend of three years, moved out of their shared Los Angeles home.

Now, Radar Online is reporting that the two are fighting over custody of Bear.

"After Rob moved his things out of their Los Angeles home, he then told Kristen he wanted Bear," an insider revealed to Radar Online.

Stewart's not ready to give up just yet on Bear though, reportedly settling for joint custody.

"She was heartbroken," the source continued. "They adopted Bear together and she always felt that he was their little baby. But Rob was so hurt by Kristen's actions he decided that he wants the dog to help him get over what happened. After all, a dog is man's best friend and Bear is such a good companion."

Before the highly publicized fall out, the former on-screen and off-screen lovers reportedly had plans to adopt another dog. The Daily Mail reports that they were looking for a playmate for Bear, and searching PetFinder.com along with high-kill shelters in the Los Angeles area.

While Stewart and Pattinson are said to be not on speaking terms, it seems like Sanders may be trying to work things out with his wife, Liberty Ross. TMZ found Sanders walking around in L.A. still sporting his wedding ring.

Last week Us Weekly published steamy photos of Kristen Stewart , 22, in an intimate embrace with Rupert Sanders, 41 on July 17. Stewart and Sanders met while filming 2012's "Snow White and the Huntsman," a film that also featured Sanders wife and two children.