From WENN.com

The former Charmed star's pooch was struck down with serious medical problems last month (Jan13), when he was diagnosed with an unknown form of cancer, and now Milano's pet has lost his battle with the disease.

In a post on Twitter.com, the actress writes, ""Rest in peace, my beautiful Diesel. I hope you're playing Frisbee at the dog park in the sky. I love you forever.""

Thankfully, the 40 year old has a handful of other animals to help comfort her during this difficult time - she also has 10 horses and four other pups, Dodger, Lucy, Gibson and Quixie.